阅读说明：本技术 电源变换器并机系统三相输出电压平衡控制方法及装置 (Three-phase output voltage balance control method and device for parallel operation system of power converter ) 是由 周超伟 苏景山 周圣焱 于 2020-05-26 设计创作，主要内容包括：本发明适用于电源技术领域,提供了一种电源变换器并机系统三相输出电压平衡控制方法及装置,该方法包括：根据电源变换器并机系统的三相输出电压,获取电源变换器主机的负序比例调节系数和负序积分调节系数,以及电源变换器从机的负序比例调节系数和负序积分调节系数；以及电源变换器主机的第一电压调节量；并更新电源变换器从机的负序积分调节系数,进而获得电源变换器从机的第二电压调节量；根据第一电压调节量和第二电压调节量对电源变换器并机系统进行调节,确定调节后的电源变换器并机系统的三相输出电压平衡。以使电源变换器并机系统中的并机遵循相同的控制效果,达到三相输出电压平衡,提高电源变换器并机系统三相输出电压的质量。(The invention is suitable for the technical field of power supplies, and provides a three-phase output voltage balance control method and a device for a parallel operation system of a power converter, wherein the method comprises the following steps: acquiring a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a power converter main machine and a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a power converter slave machine according to three-phase output voltage of a power converter parallel system; and a first voltage adjustment amount of the power converter host; updating a negative sequence integral regulating coefficient of the power converter slave computer, and further obtaining a second voltage regulating quantity of the power converter slave computer; and adjusting the power converter parallel system according to the first voltage adjustment quantity and the second voltage adjustment quantity, and determining the three-phase output voltage balance of the adjusted power converter parallel system. Therefore, the parallel operation in the parallel operation system of the power converter follows the same control effect, the balance of three-phase output voltage is achieved, and the quality of the three-phase output voltage of the parallel operation system of the power converter is improved.)

1. A three-phase output voltage balance control method of a power converter parallel system, the power converter parallel system comprises a power converter main machine and at least one power converter slave machine which is connected with the power converter main machine in parallel, the output end of the power converter main machine is connected with the output end of the at least one power converter slave machine to form the output end of the power converter parallel system, and the three-phase output voltage balance control method is characterized by comprising the following steps:

acquiring a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a power converter main machine and a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a power converter slave machine according to the three-phase output voltage of the power converter parallel system;

obtaining a first voltage regulating quantity of the power converter host according to a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter host;

updating a negative sequence integral regulating coefficient of the power converter slave according to the negative sequence integral regulating coefficient of the power converter master, and obtaining a second voltage regulating quantity of the power converter slave according to the updated negative sequence integral regulating coefficient of the power converter slave and the negative sequence proportional regulating coefficient of the power converter slave;

and adjusting the power converter parallel system according to the first voltage adjustment amount and the second voltage adjustment amount, and determining the three-phase output voltage balance of the power converter parallel system according to the adjusted three-phase output voltage of the power converter parallel system.

2. The method for controlling balance of three-phase output voltages of a power converter parallel system according to claim 1, wherein the obtaining of the negative sequence proportional regulating coefficient and the negative sequence integral regulating coefficient of the power converter master and the negative sequence proportional regulating coefficient and the negative sequence integral regulating coefficient of the power converter slave according to the three-phase output voltages of the power converter parallel system comprises:

according to the three-phase output voltage of the parallel operation system of the power converter, carrying out proportional integral regulation on the three-phase output voltage under a negative sequence rotating coordinate system through a proportional integral regulator of a main machine of the power converter to obtain a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the main machine of the power converter;

and according to the three-phase output voltage of the parallel operation system of the power converter, carrying out proportional integral regulation on the three-phase output voltage under a negative sequence rotation coordinate system through a proportional integral regulator of a slave of the power converter to obtain a negative sequence proportional regulation coefficient and a negative sequence integral regulation coefficient of the slave of the power converter.

3. The method for controlling balance of three-phase output voltages of a power converter parallel system according to claim 2, wherein the obtaining of the negative sequence proportional regulating coefficient and the negative sequence integral regulating coefficient of the power converter main unit by performing proportional integral regulation on the three-phase output voltages in a negative sequence rotation coordinate system through a proportional integral regulator of the power converter main unit according to the three-phase output voltages of the power converter parallel system comprises:

the power converter host performs negative sequence rotation coordinate conversion on the three-phase output voltage to obtain a negative sequence voltage component;

low-pass filtering the negative sequence voltage component to obtain a stable negative sequence voltage component;

subtracting the stable negative sequence voltage component from a voltage reference value input into the parallel operation system of the power converter to obtain a negative sequence voltage error value;

and carrying out proportional integral adjustment on the negative sequence voltage error value through a proportional integral adjuster of the power converter host to obtain a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the power converter host.

4. The method for controlling the three-phase output voltage balance of the parallel operation system of the power converters as claimed in claim 1, wherein the obtaining of the first voltage regulating quantity of the power converter main unit according to the negative sequence proportional regulating coefficient and the negative sequence integral regulating coefficient of the power converter main unit comprises:

obtaining a negative sequence voltage regulating quantity of the power converter host according to a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter host;

and performing negative sequence rotation coordinate inverse transformation on the negative sequence voltage regulating quantity to obtain a first voltage regulating quantity of the power converter host.

5. The method for controlling the balance of the three-phase output voltages of the power converter parallel system according to claim 1, wherein the adjusting the power converter parallel system according to the first voltage adjustment amount and the second voltage adjustment amount to balance the current three-phase output voltages of the power converter parallel system comprises:

regulating the reference voltage output by the power converter host according to the first voltage regulating quantity, and converting the regulated voltage to obtain a pulse width modulation waveform output by the power converter host;

regulating the reference voltage output by the power converter slave according to the second voltage regulating quantity, and converting the regulated voltage to obtain a pulse width modulation waveform output by the power converter slave;

inputting a pulse width modulation waveform of the power converter host into a driver corresponding to the power converter host, so that the driver corresponding to the power converter host drives an inverter corresponding to the power converter host to obtain a first three-phase output voltage;

when the voltage amplitudes of the phases of the first three-phase output voltage are the same, determining that the current three-phase output voltage of the power converter main machine is balanced;

inputting a pulse width modulation waveform of the power converter slave to a driver corresponding to the power converter slave, and enabling the driver corresponding to the power converter slave to drive an inverter corresponding to the power converter slave to obtain a second three-phase output voltage;

and when the voltage amplitudes of the phases of the second three-phase output voltage are the same, determining that the current three-phase output voltage of the power converter slave machine is balanced, and determining that the current three-phase output voltage of the power converter parallel system is balanced.

6. The method according to claim 5, wherein when the amplitudes of the voltages of the first three-phase output voltage are different, the first voltage adjustment amount of the power converter main unit is updated according to a manner of obtaining the first voltage adjustment amount of the power converter main unit;

and updating the first three-phase output voltage according to the updated first voltage regulating quantity of the power converter main machine until the voltage amplitudes of all phases of the updated first three-phase output voltage are the same, and determining the current three-phase output voltage balance of the power converter main machine.

7. A three-phase output voltage balance control device of a parallel operation system of power converters is characterized by comprising the following components:

the proportional-integral regulating module is used for acquiring a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter master machine and a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter slave machine according to the three-phase output voltage of the power converter parallel system;

the first voltage regulating quantity obtaining module is used for obtaining a first voltage regulating quantity of the power converter host according to a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter host;

the second voltage regulating quantity obtaining module is used for updating a negative sequence integral regulating coefficient of the power converter slave according to the negative sequence integral regulating coefficient of the power converter master and obtaining a second voltage regulating quantity of the power converter slave according to the updated negative sequence integral regulating coefficient of the power converter slave and the negative sequence proportional regulating coefficient of the power converter slave;

and the control module is used for adjusting the power converter parallel system according to the first voltage adjustment amount and the second voltage adjustment amount and determining the three-phase output voltage balance of the power converter parallel system according to the adjusted three-phase output voltage of the power converter parallel system.

8. The power converter parallel system three-phase output voltage balance control device of claim 7, wherein the proportional-integral regulating module comprises:

the main machine proportion-integral regulating unit is used for carrying out proportion-integral regulation on the three-phase output voltage under a negative sequence rotating coordinate system through a proportion-integral regulator of the main machine of the power converter according to the three-phase output voltage of the parallel system of the power converter, and acquiring a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of the main machine of the power converter;

and the slave proportional-integral regulating unit is used for carrying out proportional-integral regulation on the three-phase output voltage under a negative sequence rotation coordinate system through a proportional-integral regulator of the slave of the power converter according to the three-phase output voltage of the parallel system of the power converter, and acquiring a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the slave of the power converter.

9. A terminal device comprising a memory, a processor and a computer program stored in the memory and operable on the processor, wherein the processor executes the computer program to implement the steps of the method for controlling the three-phase output voltage balance of the parallel operation system of the power converters according to any one of claims 1 to 6.

10. A computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor to implement the steps of the method for controlling the three-phase output voltage balance of the parallel operation system of the power converters according to any one of claims 1 to 6.

Technical Field

The invention belongs to the technical field of uninterruptible power supplies, and particularly relates to a three-phase output voltage balance control method and device for a parallel operation system of a power converter.

Background

An Uninterruptible Power supply (Uninterruptible Power System, Power converter) is an energy conversion device that uses battery chemical energy as backup energy to uninterruptedly supply ac Power to user equipment when a mains failure such as a mains Power outage occurs. The emergency power supply can be used as an emergency, so that the normal work is prevented from being influenced by sudden power failure, and the equipment and data are prevented from being damaged; the power supply pollution such as surge, instant high voltage, instant low voltage, wire noise and frequency deviation on the mains supply can be eliminated, the power supply quality is improved, and a high-quality power supply is provided for the system. With the development of information technology, the demand for high-capacity and high-reliability power converters is increasing day by day, and a parallel system of the power converters is not only easy to realize system capacity expansion, but also increases redundant backup so as to improve the reliability of a power supply system, and has become a key technology in the power converter industry.

The symmetry of the output voltage is an important performance index of a three-phase power converter power supply and even three-phase alternating-current voltage, and in practical application, the three-phase power converter is generally required to have the capability of supplying power to balanced and unbalanced loads at the same time, and the same is true for a parallel operation system of the three-phase power converter. The unbalanced load of the parallel system of the three-phase power converter is unavoidable, so that unbalanced three-phase output voltage is generated when the parallel system of the three-phase power converter supplies power to the unbalanced load, the output voltage waveform is distorted, and the quality of the output voltage of the parallel system of the three-phase power converter is affected.

Disclosure of Invention

In view of this, embodiments of the present invention provide a method and an apparatus for controlling balance of three-phase output voltages of a parallel-connected power converter, so as to solve the problems of unbalanced three-phase output voltages and poor quality of output voltages when a parallel-connected system of three-phase power converters in the prior art is loaded with an unbalanced load.

The first aspect of the embodiments of the present invention provides a three-phase output voltage balance control method for a power converter parallel system, where the power converter parallel system includes a power converter master and at least one power converter slave connected in parallel to the power converter master, an output end of the power converter master is connected to an output end of the at least one power converter slave to form an output end of the power converter parallel system, and the three-phase output voltage balance control method for the power converter parallel system includes:

acquiring a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a power converter main machine and a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a power converter slave machine according to the three-phase output voltage of the power converter parallel system;

obtaining a first voltage regulating quantity of the power converter host according to a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter host;

updating a negative sequence integral regulating coefficient of the power converter slave according to the negative sequence integral regulating coefficient of the power converter master, and obtaining a second voltage regulating quantity of the power converter slave according to the updated negative sequence integral regulating coefficient of the power converter slave and the negative sequence proportional regulating coefficient of the power converter slave;

and adjusting the power converter parallel system according to the first voltage adjustment amount and the second voltage adjustment amount, and determining the three-phase output voltage balance of the power converter parallel system according to the adjusted three-phase output voltage of the power converter parallel system.

Optionally, the obtaining a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the power converter master and a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the power converter slave according to the three-phase output voltage of the power converter parallel system includes:

according to the three-phase output voltage of the parallel operation system of the power converter, carrying out proportional integral regulation on the three-phase output voltage under a negative sequence rotating coordinate system through a proportional integral regulator of a main machine of the power converter to obtain a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the main machine of the power converter;

and according to the three-phase output voltage of the parallel operation system of the power converter, carrying out proportional integral regulation on the three-phase output voltage under a negative sequence rotation coordinate system through a proportional integral regulator of a slave of the power converter to obtain a negative sequence proportional regulation coefficient and a negative sequence integral regulation coefficient of the slave of the power converter.

Optionally, the performing, according to the three-phase output voltage of the parallel operation system of the power converters, proportional-integral adjustment on the three-phase output voltage in a negative sequence rotation coordinate system by using a proportional-integral adjuster of the power converter main unit to obtain a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the power converter main unit includes:

the power converter host performs negative sequence rotation coordinate conversion on the three-phase output voltage to obtain a negative sequence voltage component;

low-pass filtering the negative sequence voltage component to obtain a stable negative sequence voltage component;

subtracting the stable negative sequence voltage component from a voltage reference value input into the parallel operation system of the power converter to obtain a negative sequence voltage error value;

and carrying out proportional integral adjustment on the negative sequence voltage error value through a proportional integral adjuster of the power converter host to obtain a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the power converter host.

Optionally, the obtaining a first voltage adjustment quantity of the power converter host according to the negative sequence proportional adjustment coefficient and the negative sequence integral adjustment coefficient of the power converter host includes:

obtaining a negative sequence voltage regulating quantity of the power converter host according to a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter host;

and performing negative sequence rotation coordinate inverse transformation on the negative sequence voltage regulating quantity to obtain a first voltage regulating quantity of the power converter host.

Optionally, the adjusting the power converter parallel operation system according to the first voltage adjustment amount and the second voltage adjustment amount to balance the current three-phase output voltage of the power converter parallel operation system includes:

regulating the reference voltage output by the power converter host according to the first voltage regulating quantity, and converting the regulated voltage to obtain a pulse width modulation waveform output by the power converter host;

regulating the reference voltage output by the power converter slave according to the second voltage regulating quantity, and converting the regulated voltage to obtain a pulse width modulation waveform output by the power converter slave;

inputting a pulse width modulation waveform of the power converter host into a driver corresponding to the power converter host, so that the driver corresponding to the power converter host drives an inverter corresponding to the power converter host to obtain a first three-phase output voltage;

when the voltage amplitudes of the phases of the first three-phase output voltage are the same, determining that the current three-phase output voltage of the power converter main machine is balanced;

inputting a pulse width modulation waveform of the power converter slave to a driver corresponding to the power converter slave, and enabling the driver corresponding to the power converter slave to drive an inverter corresponding to the power converter slave to obtain a second three-phase output voltage;

and when the voltage amplitudes of the phases of the second three-phase output voltage are the same, determining that the current three-phase output voltage of the power converter slave machine is balanced, and determining that the current three-phase output voltage of the power converter parallel system is balanced.

Optionally, when the amplitudes of the voltages of the phases of the first three-phase output voltage are different, updating the first voltage adjustment quantity of the power converter host according to a manner of obtaining the first voltage adjustment quantity of the power converter host;

and updating the first three-phase output voltage according to the updated first voltage regulating quantity of the power converter main machine until the voltage amplitudes of all phases of the updated first three-phase output voltage are the same, and determining the current three-phase output voltage balance of the power converter main machine.

A second aspect of the embodiments of the present invention provides a three-phase output voltage balance control device for a parallel operation system of power converters, including:

the proportional-integral regulating module is used for acquiring a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter master machine and a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter slave machine according to the three-phase output voltage of the power converter parallel system;

the first voltage regulating quantity obtaining module is used for obtaining a first voltage regulating quantity of the power converter host according to a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter host;

the second voltage regulating quantity obtaining module is used for updating a negative sequence integral regulating coefficient of the power converter slave according to the negative sequence integral regulating coefficient of the power converter master and obtaining a second voltage regulating quantity of the power converter slave according to the updated negative sequence integral regulating coefficient of the power converter slave and the negative sequence proportional regulating coefficient of the power converter slave;

and the control module is used for adjusting the power converter parallel system according to the first voltage adjustment amount and the second voltage adjustment amount and determining the three-phase output voltage balance of the power converter parallel system according to the adjusted three-phase output voltage of the power converter parallel system.

Optionally, the proportional-integral adjusting module includes:

the main machine proportion-integral regulating unit is used for carrying out proportion-integral regulation on the three-phase output voltage under a negative sequence rotating coordinate system through a proportion-integral regulator of the main machine of the power converter according to the three-phase output voltage of the parallel system of the power converter, and acquiring a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of the main machine of the power converter;

and the slave proportional-integral regulating unit is used for carrying out proportional-integral regulation on the three-phase output voltage under a negative sequence rotation coordinate system through a proportional-integral regulator of the slave of the power converter according to the three-phase output voltage of the parallel system of the power converter, and acquiring a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the slave of the power converter.

A third aspect of an embodiment of the present invention provides a terminal device, including: the power converter parallel machine system comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to realize the steps of the power converter parallel machine system three-phase output voltage balance control method.

A fourth aspect of the embodiments of the present invention provides a computer-readable storage medium, where a computer program is stored, and the computer program, when executed by a processor, implements the steps of the method for controlling three-phase output voltage balance of a parallel power converter system of any one of the above power converters.

Compared with the prior art, the embodiment of the invention has the following beneficial effects: the method comprises the steps that a negative sequence proportion regulation coefficient and a negative sequence integral regulation coefficient of a power converter master machine, and a negative sequence proportion regulation coefficient and a negative sequence integral regulation coefficient of a power converter slave machine are obtained; obtaining a first voltage regulating quantity of the power converter host according to a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter host; updating a negative sequence integral regulating coefficient of a power converter slave according to the negative sequence integral regulating coefficient of the power converter master, and obtaining a second voltage regulating quantity of the power converter slave according to the updated negative sequence integral regulating coefficient of the power converter slave and the negative sequence proportional regulating coefficient of the power converter slave; and adjusting the power converter parallel system according to the first voltage adjustment amount and the second voltage adjustment amount, and determining the three-phase output voltage balance of the power converter parallel system according to the adjusted three-phase output voltage of the power converter parallel system. The problem that when the power converter master machine and the power converter slave machine respectively carry out proportional integral adjustment, due to the fact that historical information of an integral part in a proportional integral regulator is accumulated, the difference of adjustment quantity between the power converter slave machine and the power converter master machine is gradually increased, the second voltage adjustment quantity of the power converter slave machine is inconsistent with the first voltage adjustment quantity of the power converter master machine, and therefore three-phase output voltage of a power converter parallel operation system is unbalanced is solved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic flow chart of an implementation of a three-phase output voltage balance control method of a parallel operation system of a power converter according to an embodiment of the present invention;

fig. 2 is a block diagram of three-phase output voltage balance control of a parallel operation system of power converters provided by an embodiment of the invention;

fig. 3 is a schematic block diagram illustrating a control principle of a power converter master or a power converter slave according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a three-phase output voltage balance control device of a parallel operation system of power converters provided by an embodiment of the invention;

fig. 5 is a schematic diagram of a terminal device according to an embodiment of the present invention.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

In order to explain the technical means of the present invention, the following description will be given by way of specific examples.

Fig. 1 is a schematic flow chart of an implementation of a three-phase output voltage balance control method of a parallel operation system of a power converter according to an embodiment of the present invention, which is described in detail below.

Step 101, acquiring a negative sequence proportion regulation coefficient and a negative sequence integral regulation coefficient of a power converter main machine and a negative sequence proportion regulation coefficient and a negative sequence integral regulation coefficient of a power converter slave machine according to three-phase output voltage of a power converter parallel system.

Referring to fig. 2, the power converter parallel system may be a UPS parallel system or a pv inverter parallel system, where the UPS parallel system is taken as an example, the UPS parallel system includes a UPS master and at least one UPS slave connected in parallel to the UPS master, and an output of the UPS master is connected to an output of the at least one UPS slave to form an output of the UPS parallel system.

Optionally, obtaining the negative sequence proportional adjustment coefficient and the negative sequence integral adjustment coefficient of the power converter master and the negative sequence proportional adjustment coefficient and the negative sequence integral adjustment coefficient of the power converter slave according to the three-phase output voltage of the parallel system of the power converters may include:

according to the three-phase output voltage of the parallel operation system of the power converter, the proportional-integral regulator of the main machine of the power converter is used for carrying out proportional-integral regulation on the three-phase output voltage under a negative sequence rotating coordinate system to obtain a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the main machine of the power converter.

Optionally, the power converter host may perform negative sequence rotation coordinate transformation on the three-phase output voltage to obtain a negative sequence voltage component, perform low-pass filtering on the negative sequence voltage component to obtain a stable negative sequence voltage component, perform proportional-integral adjustment on the negative sequence voltage error value by subtracting the stable negative sequence voltage component from a voltage reference value input to the power converter parallel system to obtain a negative sequence voltage error value, and perform proportional-integral adjustment on the negative sequence voltage error value by using a proportional-integral regulator of the power converter host to obtain a negative sequence proportional-adjustment coefficient and a negative sequence integral-adjustment coefficient of the power converter host.

With reference to fig. 2 and 3, for the UPS parallel operation system, the three-phase output voltage U of the UPS parallel operation system collected by the sampling module of the UPS host may be utilized_a、U_b、U_cOutput three-phase voltage U_a、U_b、U_cInputting the abc/dqo negative sequence conversion unit in the UPS host control module to output three-phase output voltage U_a、U_b、U_cCarrying out abc/dqo negative sequence rotation coordinate transformation to obtain a negative sequence voltage component U_d、U_qNegative sequence voltage component U_d、U_qThe stable negative sequence voltage component U 'can be obtained by low-pass filtering through a low-pass filter'_d、U′_qA stable negative-sequence voltage component U'_d、U′_qAnd the voltage reference value U input into the UPS parallel operation system_refAnd performing proportional integral adjustment on the negative sequence voltage error values of the d axis and the q axis of the UPS host through a proportional integral adjuster of the UPS host, and obtaining a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the UPS host.

According to the three-phase output voltage of the UPS parallel machine system, the proportional integral regulator of the UPS slave machine is used for carrying out proportional integral regulation on the three-phase output voltage under a negative sequence rotating coordinate system, and a negative sequence proportional regulation coefficient and a negative sequence integral regulation coefficient of the UPS slave machine are obtained.

Similarly, in conjunction with fig. 2 and 3, the UPS slave may use a sampling module common to the UPS master, or a three-phase output voltage U of the UPS parallel operation system collected by the UPS slave's own sampling module_a、U_b、U_cOutputting the three-phase output voltage U through an abc/dqo negative sequence conversion unit in the UPS slave control module_a、U_b、U_cCarrying out abc/dqo negative sequence rotation coordinate transformation to obtain a negative sequence voltage component U_d、U_qThrough lowPass filter for negative sequence voltage component U_d、U_qThe low-pass filtering is carried out to obtain a stable negative sequence voltage component U'_d、U′_qA stable negative-sequence voltage component U'_d、U′_qAnd the voltage reference value U input into the UPS parallel operation system_refAnd performing proportional integral adjustment on the negative sequence voltage error values of the d axis and the q axis of the UPS slave through a proportional integral adjuster of the UPS slave, so as to obtain a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the UPS slave.

The three-phase voltage refers to A, B, C three-phase voltage with the phase difference of 120 degrees, wherein the phase A leads the phase B by 120 degrees, the phase B leads the phase C by 120 degrees, and the phase C leads the phase A by 120 degrees, which is called as a positive sequence; the phase A is 120 degrees behind the phase B, the phase B is 120 degrees behind the phase C, the phase C is 120 degrees behind the phase A, and the phase C is called as a negative sequence; the three phases of the A phase, the B phase and the C phase are the same and are called zero sequences. The three-phase output voltage of the power converter parallel system is decomposed into three parts of a positive sequence, a negative sequence and a zero sequence, when the three-phase output voltage is balanced, only a positive sequence component exists, and when a negative sequence component exists, the three-phase output voltage is unbalanced, so that the three-phase output voltage of the power converter parallel system is adjusted according to the negative sequence component of the three-phase output voltage, and the three-phase output voltage unbalance of the power converter parallel system can be eliminated.

The three-phase voltage under the three-phase static coordinate system has the characteristics of clear physical significance, intuition and the like, but under the three-phase static coordinate system, the three-phase alternating voltage belongs to time-varying information and is not easy to control, so that the three-phase voltage under the three-phase static coordinate system is converted into a two-phase static coordinate system through Clark conversion, and is converted into d/q axis voltage of a two-phase rotating coordinate system through Park conversion, and the three-phase voltage is convenient to control and adjust through the d/q axis voltage.

And 102, obtaining a first voltage regulating quantity of the power converter host according to the negative sequence proportional regulating coefficient and the negative sequence integral regulating coefficient of the power converter host.

Optionally, referring to fig. 3, according to the negative sequence proportional adjustment coefficient and the negative sequence integral adjustment coefficient of the power converter host, the negative sequence voltage adjustment quantity of the power converter host output by the proportional-integral regulator may be obtained, and dqo/abc negative sequence rotation coordinate inverse transformation is performed on the negative sequence voltage adjustment quantity of the power converter host, so as to obtain the first voltage adjustment quantity of the power converter host.

Taking a UPS parallel operation system as an example, according to a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of a UPS host, a negative sequence voltage adjustment quantity of the UPS host output by a proportional-integral regulator can be obtained, and a dqo/abc negative sequence rotation coordinate inverse transformation is performed on the negative sequence voltage adjustment quantity of the UPS host, so that a first voltage adjustment quantity of the UPS host can be obtained.

And 103, updating the negative sequence integral regulating coefficient of the power converter slave according to the negative sequence integral regulating coefficient of the power converter master, and obtaining a second voltage regulating quantity of the power converter slave according to the updated negative sequence integral regulating coefficient of the power converter slave and the negative sequence proportional regulating coefficient of the power converter slave.

Taking the UPS parallel operation system as an example, for the proportional-integral regulator of the UPS slave, because the integral part in the proportional-integral regulator accumulates the history information, after the UPS parallel operation system operates for a period of time, the difference between the history information accumulated by the inverter of the UPS slave and the history information accumulated by the inverter of the UPS master becomes larger gradually, and finally, the difference between the second voltage regulating quantity of the UPS slave and the first voltage regulating quantity of the UPS parallel operation becomes larger and larger, and finally, a larger parallel operation circulating current is caused, so that the three-phase voltage of the UPS parallel operation system is unbalanced.

In order to eliminate the influence, the negative sequence integral regulating coefficient of the UPS host machine CAN be obtained through the CAN bus, the negative sequence integral regulating coefficient of the UPS slave machine is updated according to the negative sequence integral regulating coefficient of the UPS host machine, and the second voltage regulating quantity of the UPS slave machine is obtained according to the updated negative sequence integral regulating coefficient of the UPS slave machine and the negative sequence proportional regulating coefficient of the UPS slave machine, so that the second voltage regulating quantity of the UPS slave machine is consistent with the first voltage regulating quantity of the UPS host machine, parallel machine circulation is avoided, parallel machines in the UPS parallel machine system follow the same control effect, and the three-phase output voltage of the UPS parallel machine system is balanced.

The second voltage regulating quantity of the UPS slave machine is consistent with the first voltage regulating quantity of the UPS host machine, parallel operation circulation is avoided, parallel operation in the UPS parallel operation system follows the same control effect, and three-phase output voltage of the UPS parallel operation system is balanced.

And 104, adjusting the parallel operation system of the power converters according to the first voltage adjustment amount and the second voltage adjustment amount, and determining the three-phase output voltage balance of the parallel operation system of the power converters according to the adjusted three-phase output voltage of the parallel operation system of the power converters.

Optionally, with reference to fig. 2 and fig. 3, the reference voltage of the power converter host obtained through the main loop is adjusted according to the first voltage adjustment amount of the power converter host, and the adjusted voltage is converted, so that a pulse width modulation waveform output by the power converter host can be obtained, the pulse width modulation waveform of the power converter host is input to a driver corresponding to the power converter host, so that the driver corresponding to the power converter host drives an inverter corresponding to the power converter host, and a first three-phase output voltage of the power converter host is obtained, and when the voltage amplitudes of the phases of the first three-phase output voltage of the power converter host are the same, it is determined that the current three-phase output voltage of the power converter host is balanced.

Optionally, when the amplitudes of the voltages of the first three-phase output voltage are different, the first voltage adjustment amount of the power converter host may be updated according to the manner of obtaining the first voltage adjustment amount of the power converter host, the first three-phase output voltage of the power converter host is updated according to the updated first voltage adjustment amount of the power converter host, and the current three-phase output voltage balance of the power converter host is determined until the amplitudes of the voltages of the phases of the first three-phase output voltage of the updated power converter host are the same.

Optionally, with reference to fig. 2 and fig. 3, the reference voltage of the power converter slave obtained through the main loop is adjusted according to the second voltage adjustment amount of the power converter slave, and the adjusted voltage is converted, so as to obtain a pulse width modulation waveform output by the power converter slave, the pulse width modulation waveform of the power converter slave is input to a driver corresponding to the power converter slave, so that the driver corresponding to the power converter slave drives an inverter corresponding to the power converter slave, and a second three-phase output voltage of the power converter slave is obtained, when the phase output voltage amplitudes of the second three-phase output voltage of the power converter slave are the same, it is determined that the current three-phase output voltage of the power converter slave is balanced, and the current three-phase output voltage of the power converter parallel operation system is balanced.

According to the three-phase output voltage balance control method of the parallel operation system of the power converter, a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a main machine of the power converter and a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a slave machine of the power converter are obtained; obtaining a first voltage regulating quantity of the power converter host according to a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter host; updating a negative sequence integral regulating coefficient of a power converter slave according to the negative sequence integral regulating coefficient of the power converter master, and obtaining a second voltage regulating quantity of the power converter slave according to the updated negative sequence integral regulating coefficient of the power converter slave and the negative sequence proportional regulating coefficient of the power converter slave; and adjusting the power converter parallel system according to the first voltage adjustment amount and the second voltage adjustment amount, and determining the three-phase output voltage balance of the power converter parallel system according to the adjusted three-phase output voltage of the power converter parallel system. The problem that when the power converter master machine and the power converter slave machine respectively carry out proportional integral adjustment, due to the accumulation of historical information of an integral part in a proportional integral adjuster, the difference of adjustment quantity between the power converter slave machine and the power converter master machine is gradually increased, and the second voltage adjustment quantity of the power converter slave machine is inconsistent with the first voltage adjustment quantity of the power converter master machine is solved, so that the voltage adjustment quantity of a power converter parallel operation system is consistent, parallel operation circulation is avoided, and the three-phase output voltage of the power converter parallel operation system is balanced.

It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

Fig. 4 shows an exemplary diagram of a three-phase output voltage balance control device of a power converter parallel operation system according to an embodiment of the present invention, which corresponds to the three-phase output voltage balance control method of the power converter parallel operation system according to the foregoing embodiment. As shown in fig. 4, the apparatus may include: a proportional-integral adjustment module 41, a first voltage adjustment amount acquisition module 42, a second voltage adjustment amount acquisition module 43, and a control module 44.

A proportional-integral regulating module 41, configured to obtain a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter master and a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the power converter slave according to the three-phase output voltage of the parallel system of the power converters;

a first voltage adjustment quantity obtaining module 42, configured to obtain a first voltage adjustment quantity of the power converter host according to a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the power converter host;

a second voltage adjustment quantity obtaining module 43, configured to update a negative sequence integral adjustment coefficient of the power converter slave according to the negative sequence integral adjustment coefficient of the power converter master, and obtain a second voltage adjustment quantity of the power converter slave according to the updated negative sequence integral adjustment coefficient of the power converter slave and the negative sequence proportional adjustment coefficient of the power converter slave;

and the control module 44 is configured to adjust the power converter parallel system according to the first voltage adjustment amount and the second voltage adjustment amount, and determine a three-phase output voltage balance of the power converter parallel system according to the adjusted three-phase output voltage of the power converter parallel system.

Optionally, the proportional-integral adjusting module 41 may include:

the main machine proportion-integral regulating unit is used for carrying out proportion-integral regulation on the three-phase output voltage under a negative sequence rotating coordinate system through a proportion-integral regulator of the main machine of the power converter according to the three-phase output voltage of the parallel system of the power converter, and acquiring a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of the main machine of the power converter;

and the slave proportional-integral regulating unit is used for carrying out proportional-integral regulation on the three-phase output voltage under a negative sequence rotation coordinate system through a proportional-integral regulator of the slave of the power converter according to the three-phase output voltage of the parallel system of the power converter, and acquiring a negative sequence proportional regulating coefficient and a negative sequence integral regulating coefficient of the slave of the power converter.

Optionally, the proportional-integral adjusting module 41 may be configured to perform negative sequence rotation coordinate transformation on the three-phase output voltage by the power converter host to obtain a negative sequence voltage component; low-pass filtering the negative sequence voltage component to obtain a stable negative sequence voltage component; subtracting the stable negative sequence voltage component from a voltage reference value input into the parallel operation system of the power converter to obtain a negative sequence voltage error value; and carrying out proportional integral adjustment on the negative sequence voltage error value through a proportional integral adjuster of the power converter host to obtain a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the power converter host.

Optionally, the first voltage adjustment quantity obtaining module 42 may be configured to obtain a negative sequence voltage adjustment quantity of the power converter host according to a negative sequence proportional adjustment coefficient and a negative sequence integral adjustment coefficient of the power converter host; and performing negative sequence rotation coordinate inverse transformation on the negative sequence voltage regulating quantity to obtain a first voltage regulating quantity of the power converter host.

Optionally, the control module 44 may be configured to adjust the reference voltage output by the power converter host according to the first voltage adjustment amount, and convert the adjusted voltage to obtain a pulse width modulation waveform output by the power converter host; regulating the reference voltage output by the power converter slave according to the second voltage regulating quantity, and converting the regulated voltage to obtain a pulse width modulation waveform output by the power converter slave; inputting a pulse width modulation waveform of the power converter host into a driver corresponding to the power converter host, so that the driver corresponding to the power converter host drives an inverter corresponding to the power converter host to obtain a first three-phase output voltage; when the voltage amplitudes of the phases of the first three-phase output voltage are the same, determining that the current three-phase output voltage of the power converter main machine is balanced; inputting a pulse width modulation waveform of the power converter slave to a driver corresponding to the power converter slave, and enabling the driver corresponding to the power converter slave to drive an inverter corresponding to the power converter slave to obtain a second three-phase output voltage; and when the amplitude of the second three-phase output voltage is the same as that of the first three-phase output voltage, determining that the current three-phase output voltage of the power converter slave is balanced, and determining that the current three-phase output voltage of the power converter parallel system is balanced.

Optionally, the control module 44 may be configured to update the first voltage adjustment amount of the power converter host according to a manner of obtaining the first voltage adjustment amount of the power converter host when amplitudes of voltages of each phase of the first three-phase output voltage are different; and updating the first three-phase output voltage according to the updated first voltage regulating quantity of the power converter main machine until the voltage amplitudes of all phases of the updated first three-phase output voltage are the same, and determining the current three-phase output voltage balance of the power converter main machine.

Optionally, the control module 44 may be configured to, when the amplitude of the second three-phase output voltage is different from the amplitude of the first three-phase output voltage, update the second three-phase output voltage according to a manner of obtaining the second three-phase output voltage until the updated second three-phase output voltage is the same as the amplitude of the first three-phase output voltage, determine that the current three-phase output voltages of the slave machines of the power converter are balanced, and determine that the current three-phase output voltages of the parallel operation system of the power converter are balanced.

The three-phase output voltage balance control device of the power converter parallel system can obtain a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a power converter master machine and a negative sequence proportion regulating coefficient and a negative sequence integral regulating coefficient of a power converter slave machine through a proportion integral regulating module, can obtain a first voltage regulating quantity of the power converter master machine through a first voltage regulating quantity obtaining module, can update the negative sequence integral regulating coefficient of a power converter slave machine according to the negative sequence integral regulating coefficient of the power converter master machine through a second voltage regulating quantity obtaining module, can obtain a second voltage regulating quantity of the power converter slave machine according to the updated negative sequence integral regulating coefficient of the power converter slave machine and the negative sequence proportion regulating coefficient of the power converter slave machine, and can regulate the power converter parallel system according to the first voltage regulating quantity and the second voltage regulating quantity through a control module, and determining the three-phase output voltage balance of the parallel system of the power converters according to the adjusted three-phase output voltage of the parallel system of the power converters. The problem that the difference of the adjustment quantity between the power converter slave machine and the power converter master machine is gradually increased and the second voltage adjustment of the power converter slave machine is inconsistent with the first voltage adjustment quantity of the power converter master machine due to the accumulation of the historical information of the integral part in the proportional-integral regulator when the power converter master machine and the power converter slave machine respectively perform proportional-integral adjustment is solved, so that the voltage adjustment quantities of the power converter parallel machine system are consistent, parallel machine circulation is avoided, and the three-phase output voltage of the power converter parallel machine system is balanced.

Fig. 5 is a schematic diagram of a terminal device according to an embodiment of the present invention. As shown in fig. 5, the terminal device 500 of this embodiment includes: a processor 501, a memory 502, and a computer program 503 stored in the memory 502 and operable on the processor 501, such as a power converter parallel machine system three-phase output voltage balance control program. The processor 501 executes the computer program 503 to implement the steps in the embodiment of the method for controlling the three-phase output voltage balance of the parallel operation system of the power converter, such as the steps 101 to 104 shown in fig. 1, and the processor 501 executes the computer program 503 to implement the functions of the modules in the embodiments of the apparatus, such as the modules 41 to 44 shown in fig. 4.

Illustratively, the computer program 503 may be partitioned into one or more program modules that are stored in the memory 502 and executed by the processor 501 to implement the present invention. The one or more program modules may be a series of computer program instruction segments capable of performing specific functions, which are used to describe the execution process of the computer program 503 in the three-phase output voltage balance control device or terminal equipment 500 of the power converter parallel system. For example, the computer program 503 may be divided into the proportional-integral adjustment module 41, the first voltage adjustment amount acquisition module 42, the second voltage adjustment amount acquisition module 43, and the control module 44, and specific functions of the modules are shown in fig. 4, which is not described herein again.

The terminal device 500 may be a desktop computer, a notebook, a palm computer, a cloud server, or other computing devices. The terminal device may include, but is not limited to, a processor 501, a memory 502. Those skilled in the art will appreciate that fig. 5 is merely an example of a terminal device 500 and is not intended to limit the terminal device 500 and may include more or fewer components than those shown, or some components may be combined, or different components, for example, the terminal device may also include input output devices, network access devices, buses, etc.

The Processor 501 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 502 may be an internal storage unit of the terminal device 500, such as a hard disk or a memory of the terminal device 500. The memory 502 may also be an external storage device of the terminal device 500, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like, which are provided on the terminal device 500. Further, the memory 502 may also include both an internal storage unit and an external storage device of the terminal device 500. The memory 502 is used for storing the computer programs and other programs and data required by the terminal device 500. The memory 502 may also be used to temporarily store data that has been output or is to be output.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/terminal device and method may be implemented in other ways. For example, the above-described embodiments of the apparatus/terminal device are merely illustrative, and for example, the division of the modules or units is only one logical division, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated modules/units, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.