阅读说明：本技术 新能源发电直驱系统 (New energy power generation direct drive system ) 是由 李宏安 刘金平 陈党民 贾亚妮 陈余平 王航 李勇 孙鸿声 田渭蓉 周宁 王小军 于 2021-09-08 设计创作，主要内容包括：本发明属于电力驱动系统,为解决光伏发电系统和风力发电系统均为间歇性发电,无法单独给连续运行的负载供电,就近消纳困难的问题,提供一种新能源发电直驱系统,包括电量管理系统、升压变压器、变频器、第一电机、第二电机、变速箱,以及光伏发电系统和/或风力发电系统,电量管理系统分别与光伏发电系统和/或风力发电系统相连,光伏发电系统的输出端和/或风力发电系统的输出端均与升压变压器的输入端相连,升压变压器的输出端与变频器的输入端相连,第一电机与变频器的输出端相连,第二电机由外部电网驱动,第一电机和第二电机通过联轴器或同步离合器相连,第二电机的输出端与外部负载相连,并通过相应控制方法使第一电机和第二电机同速运行。(The invention belongs to an electric drive system, and provides a new energy power generation direct drive system for solving the problems that a photovoltaic power generation system and a wind power generation system both generate power intermittently and cannot supply power to continuously-operated loads independently, and the consumption is difficult nearby, which comprises an electric quantity management system, a step-up transformer, a frequency converter, a first motor, a second motor, a gearbox, and a photovoltaic power generation system and/or a wind power generation system, wherein the electric quantity management system is respectively connected with the photovoltaic power generation system and/or the wind power generation system, the output end of the photovoltaic power generation system and/or the output end of the wind power generation system are connected with the input end of the step-up transformer, the output end of the step-up transformer is connected with the input end of the frequency converter, the first motor is connected with the output end of the frequency converter, the second motor is driven by an external power grid, the first motor and the second motor are connected through a coupler or a synchronous clutch, the output end of the second motor is connected with an external load, and the first motor and the second motor run at the same speed through a corresponding control method.)

1. The utility model provides a new forms of energy electricity direct drive system which characterized in that: the system comprises an electric quantity management system (5), a step-up transformer (6), a frequency converter (7), a first motor (8), a second motor (9), a gearbox (10), a control system (4), a photovoltaic power generation system (1) and/or a wind power generation system (2);

the electric quantity management system (5) is respectively connected with the photovoltaic power generation system (1) and/or the wind power generation system (2) and is used for adjusting the electric energy management of the photovoltaic power generation system (1) and/or the wind power generation system (2);

the output end of the photovoltaic power generation system (1) and/or the output end of the wind power generation system (2) are connected with the input end of a boosting transformer (6), and the output end of the boosting transformer (6) is connected with the input end of a frequency converter (7);

the first motor (8) is connected with the output end of the frequency converter (7), the second motor (9) is driven by an external power grid (12), the first motor (8) is connected with the second motor (9) through a coupler, and the output end of the second motor (9) is connected with an external load (11);

the control system (4) is respectively connected with the electric quantity management system (5) and the frequency converter (7) and is used for controlling the output of the frequency converter (7) according to a control signal sent by the electric quantity management system (5);

the first motor (8) and the second motor (9) are started by:

s1, starting the second motor (9)

The first motor (8) and the second motor (9) are disconnected, and the second motor (9) is started;

s2 starting the first motor (8)

S2.1, performing two-phase static coordinate conversion on three-phase stator current of a first motor (8) to obtain corresponding current signals under a two-phase static transformation coordinate system, and performing two-phase rotation coordinate conversion to obtain corresponding current signals under a two-phase rotation coordinate system; the corresponding current signals under the two-phase rotating coordinate system are respectively exciting current and torque current;

s2.2, comparing the difference value of the exciting current and the torque current obtained in the step S1 with a preset exciting current and a preset torque current respectively, and outputting corresponding voltage signals after current regulation;

s2.3, carrying out reverse rotation transformation on the corresponding voltage signal output in the step S2, and converting the voltage signal into a corresponding voltage signal in a two-phase static transformation coordinate system;

s2.4, inputting the corresponding voltage signal under the two-phase static transformation coordinate system and the corresponding current signal under the two-phase static transformation coordinate system obtained in the step S1 into a rotor flux linkage observation and speed observation model, and using the obtained magnetic field orientation angle for the two-phase rotation coordinate conversion in the step S1;

meanwhile, inputting a corresponding voltage signal under the two-phase static transformation coordinate system into an inverter in a frequency converter (7) for control, and further driving a first motor (8) to start;

and S3, when the first motor (8) is started in the step S2 to enable the rotating speed of the first motor (8) to reach the rotating speed of the second motor (9), the first motor (8) and the second motor (9) are connected through a coupler to enable the first motor (8) and the second motor (9) to coaxially operate.

2. The new energy power generation direct drive system as claimed in claim 1, wherein:

in step S3, after the coaxial operation, the method further includes: the first motor (8) is switched to torque loop control,

during the operation process that the first motor (8) and the second motor (9) coaxially operate to drive the external load (11) together, the first motor (8) and the second motor (9) are controlled to synchronously operate according to the following method:

if the output power of the first electric machine (8) varies:

when the frequency converter (7) controls the first motor (8) to increase the electromagnetic torque of the first motor (8), the slip of the second motor (9) is reduced;

when the frequency converter (7) controls the first motor (8) to reduce the electromagnetic torque of the first motor (8), the slip of the second motor (9) is increased;

if the output power of the second motor (9) changes:

the rotating speeds of the first motor (8) and the second motor (9) are adjusted along with the power of the first motor (8), so that the first motor (8) and the second motor (9) run at the same rotating speed.

3. A motor starting method according to claim 1 or 2, characterized in that:

in step S2.2, after the current adjustment, the step of outputting the corresponding voltage signal further includes:

and after the preset exciting current and the preset torque current are subjected to feedforward compensation respectively, adding the difference comparison results corresponding to the preset exciting current and the preset torque current.

4. The new energy power generation direct drive system as claimed in claim 3, wherein: the system also comprises a diesel generator;

the diesel generator is connected with the photovoltaic power generation system (1) and/or the wind power generation system (2) and used for supplying power to the photovoltaic power generation system (1) and/or the wind power generation system (2) before starting.

5. The new energy power generation direct drive system as claimed in claim 4, wherein: the system also comprises an energy storage system (3);

the energy storage system (3) is respectively connected with the output ends of the photovoltaic power generation system (1) and/or the wind power generation system (2) and is used for absorbing and storing redundant electric quantity generated by the photovoltaic power generation system (1) and/or the wind power generation system (2);

and the control system (4) is connected with the energy storage system (3) and is used for controlling the electric energy transmitted from the energy storage system (3) to the booster transformer (6) according to the control signal sent by the electric quantity management system (5).

6. The utility model provides a new forms of energy electricity direct drive system which characterized in that: the system comprises an electric quantity management system (5), a step-up transformer (6), a frequency converter (7), a first motor (8), a second motor (9), a gearbox (10), a control system (4), a photovoltaic power generation system (1) and/or a wind power generation system (2);

the electric quantity management system (5) is respectively connected with the photovoltaic power generation system (1) and/or the wind power generation system (2) and is used for adjusting electric energy management of the photovoltaic power generation system (1) and the wind power generation system (2);

the output end of the photovoltaic power generation system (1) and/or the output end of the wind power generation system (2) are connected with the input end of a boosting transformer (6), and the output end of the boosting transformer (6) is connected with the input end of a frequency converter (7);

the first motor (8) is connected with the output end of the frequency converter (7), the second motor (9) is driven by an external power grid (12), the first motor (8) and the second motor (9) are connected through a synchronous clutch (13), and the output end of the second motor (9) is connected with an external load (11);

the control system (4) is respectively connected with the electric quantity management system (5) and the frequency converter (7) and is used for controlling the output of the frequency converter (7) according to a control signal sent by the electric quantity management system (5);

the first motor (8) and the second motor (9) are started by:

s1, starting the second motor (9)

The first motor (8) and the second motor (9) are disconnected, and the second motor (9) is started;

s2, starting the first motor (8)

S2.1, performing two-phase static coordinate conversion on three-phase stator current of a first motor (8) to obtain corresponding current signals under a two-phase static transformation coordinate system, and performing two-phase rotation coordinate conversion to obtain corresponding current signals under a two-phase rotation coordinate system; the corresponding current signals under the two-phase rotating coordinate system are respectively exciting current and torque current;

s2.2, comparing the difference value of the exciting current and the torque current obtained in the step S1 with a preset exciting current and a preset torque current respectively, and outputting corresponding voltage signals after current regulation;

s2.3, carrying out reverse rotation transformation on the corresponding voltage signal output in the step S2, and converting the voltage signal into a corresponding voltage signal in a two-phase static transformation coordinate system;

s2.4, inputting the corresponding voltage signal under the two-phase static transformation coordinate system and the corresponding current signal under the two-phase static transformation coordinate system obtained in the step S1 into a rotor flux linkage observation and speed observation model, and using the obtained magnetic field orientation angle for the two-phase rotation coordinate conversion in the step S1;

meanwhile, inputting a corresponding voltage signal under the two-phase static transformation coordinate system into an inverter in a frequency converter (7) for control, and further driving a first motor (8) to start;

and S3, when the first motor (8) is started in the step S2 to enable the rotating speed of the first motor (8) to reach the rotating speed of the second motor (9), the first motor (8) and the second motor (9) are connected through the synchronous clutch (13) to enable the first motor (8) and the second motor (9) to coaxially run.

7. The new energy power generation direct drive system as claimed in claim 6, wherein:

in step S3, after the coaxial operation, the method further includes: the first motor (8) is switched to torque loop control,

during the operation process that the first motor (8) and the second motor (9) coaxially operate to drive the external load (11) together, the first motor (8) and the second motor (9) are controlled to synchronously operate according to the following method:

if the output power of the first electric machine (8) varies:

when the frequency converter (7) controls the first motor (8) to increase the electromagnetic torque of the first motor (8), the slip of the second motor (9) is reduced;

when the frequency converter (7) controls the first motor (8) to reduce the electromagnetic torque of the first motor (8), the slip of the second motor (9) is increased;

if the output power of the second motor (9) changes:

the rotating speeds of the first motor (8) and the second motor (9) are adjusted along with the power of the first motor (8), so that the first motor (8) and the second motor (9) run at the same rotating speed.

8. A motor starting method according to claim 6 or 7, characterized in that:

in step S2.2, after the current adjustment, the step of outputting the corresponding voltage signal further includes:

and after the preset exciting current and the preset torque current are subjected to feedforward compensation respectively, adding the difference comparison results corresponding to the preset exciting current and the preset torque current.

9. The new energy power generation direct drive system as claimed in claim 8, wherein: the system also comprises a diesel generator;

the diesel generator is connected with the photovoltaic power generation system (1) and/or the wind power generation system (2) and used for supplying power to the photovoltaic power generation system (1) and/or the wind power generation system (2) before starting.

10. The new energy power generation direct drive system as claimed in claim 9, wherein: the system also comprises an energy storage system (3);

the energy storage system (3) is respectively connected with the output ends of the photovoltaic power generation system (1) and/or the wind power generation system (2) and is used for absorbing and storing redundant electric quantity generated by the photovoltaic power generation system (1) and/or the wind power generation system (2);

and the control system (4) is connected with the energy storage system (3) and is used for controlling the electric energy transmitted from the energy storage system (3) to the booster transformer (6) according to the control signal sent by the electric quantity management system (5).

Technical Field

The invention belongs to an electric drive system, and particularly relates to a new energy power generation direct drive system.

Background

A photovoltaic power generation system is a power generation system that directly converts solar energy into electric energy using a solar cell. The photovoltaic power generation system mainly comprises a photovoltaic assembly, a combiner box, a direct-current cabinet, an alternating-current power distribution cabinet, an inverter, an energy storage system, a step-up transformer, high-voltage switch equipment, a communication and monitoring system and the like. The device has the characteristics of high reliability, long service life, no environmental pollution, independent power generation and grid-connected operation. The wind power generation system drives windmill blades to rotate by utilizing wind power, then the rotating speed is increased through the speed increaser, so that a generator generates electricity, the wind power generation system mainly comprises a machine head, a rotating body, an empennage and blades, the blades are used for receiving the wind power and are converted into electric energy through the machine head, the empennage enables the blades to always face the direction of incoming wind so as to obtain maximum wind power, the rotating body enables the machine head to flexibly rotate so as to realize the function of adjusting the direction of the empennage, a rotor of the machine head is a permanent magnet, a stator winding cuts magnetic lines of force to generate electric energy, the wind power generator outputs alternating current with 13-25V change due to unstable wind quantity, the alternating current needs to be rectified by a charger, then a storage battery is charged, the electric energy generated by the wind power generator is converted into chemical energy, and then the inverter power supply with a protection circuit is used for converting the chemical energy in a storage battery into alternating current so as to ensure stable use.

For a photovoltaic or wind power generation system and other new energy power generation systems, the photovoltaic power generation system and the wind power generation system are intermittent power generation systems, cannot independently provide a power supply for a driving system, and are generally integrated into a public network system. For a photovoltaic power generation system and a wind power generation system which operate in an isolated network, the photovoltaic power generation system and the wind power generation system are used for illumination and the like generally because the photovoltaic power generation system and the wind power generation system are intermittent power generation and are limited by natural environment and weather, and a power supply is unstable and cannot supply power to continuously operating loads independently. However, for a large-scale isolated grid operation photovoltaic power generation system and a wind power generation system, how to consume the photovoltaic power generation system and the wind power generation system nearby becomes a key problem.

Disclosure of Invention

The invention provides a new energy power generation direct drive system, which aims to solve the technical problems that the existing photovoltaic power generation system and the existing wind power generation system are both used for generating power intermittently, are limited by natural environment and weather, are unstable in power supply, cannot supply power to continuously-operated loads independently, and are difficult to consume nearby particularly for a large-scale isolated network-operated photovoltaic power generation system and a large-scale wind power generation system.

In order to achieve the purpose, the invention provides the following technical scheme:

a new energy power generation direct drive system is characterized by comprising an electric quantity management system, a step-up transformer, a frequency converter, a first motor, a second motor, a gearbox, a control system, a photovoltaic power generation system and/or a wind power generation system;

the electric quantity management system is respectively connected with the photovoltaic power generation system and/or the wind power generation system and is used for adjusting the electric energy management of the photovoltaic power generation system and/or the wind power generation system;

the output end of the photovoltaic power generation system and/or the output end of the wind power generation system are/is connected with the input end of a boosting transformer, and the output end of the boosting transformer is connected with the input end of a frequency converter;

the first motor is connected with the output end of the frequency converter, the second motor is driven by an external power grid, the first motor is connected with the second motor through a coupler, and the output end of the second motor is connected with an external load through a gearbox;

the control system is respectively connected with the electric quantity management system and the frequency converter and is used for controlling the output of the frequency converter according to the control signal sent by the electric quantity management system;

the first and second motors are started by:

s1, starting the second motor

Disconnecting the first motor and the second motor, and starting the second motor;

s2 starting the first motor

S2.1, performing two-phase static coordinate conversion on three-phase stator current of the first motor to obtain corresponding current signals under a two-phase static transformation coordinate system, and performing two-phase rotation coordinate conversion to obtain corresponding current signals under a two-phase rotation coordinate system; the corresponding current signals under the two-phase rotating coordinate system are respectively exciting current and torque current;

s2.2, comparing the difference value of the exciting current and the torque current obtained in the step S1 with a preset exciting current and a preset torque current respectively, and outputting corresponding voltage signals after current regulation;

s2.3, carrying out reverse rotation transformation on the corresponding voltage signal output in the step S2, and converting the voltage signal into a corresponding voltage signal in a two-phase static transformation coordinate system;

s2.4, inputting the corresponding voltage signal under the two-phase static transformation coordinate system and the corresponding current signal under the two-phase static transformation coordinate system obtained in the step S1 into a rotor flux linkage observation and speed observation model, and using the obtained magnetic field orientation angle for the two-phase rotation coordinate conversion in the step S1;

meanwhile, inputting a corresponding voltage signal under the two-phase static transformation coordinate system into an inverter in a frequency converter for control, and further driving a first motor to start;

and S3, when the first motor is started in the step S2 and the rotating speed of the first motor reaches the rotating speed of the second motor, the first motor and the second motor are connected through the coupler and coaxially operate.

Further, in step S3, after the coaxially operating, the method further includes: the first motor is switched to torque loop control,

during the operation process that the first motor and the second motor coaxially operate to drive the external load together, the first motor and the second motor are controlled to synchronously operate according to the following method:

if the output power of the first motor changes:

when the frequency converter controls the first motor to increase the electromagnetic torque of the first motor, the slip of the second motor is reduced;

when the frequency converter controls the first motor to reduce the electromagnetic torque of the first motor, the slip of the second motor is increased;

if the output power of the second motor changes:

the rotating speeds of the first motor and the second motor are adjusted along with the power of the first motor, so that the first motor and the second motor operate at the same rotating speed.

Further, in step S2.2, after the current adjustment, the step of outputting the corresponding voltage signal further includes:

and after the preset exciting current and the preset torque current are subjected to feedforward compensation respectively, adding the difference comparison results corresponding to the preset exciting current and the preset torque current.

Further, the device also comprises a diesel generator;

the diesel generator is connected with the photovoltaic power generation system and/or the wind power generation system and used for supplying power to the photovoltaic power generation system and/or the wind power generation system before starting.

Further, the system also comprises an energy storage system;

the energy storage system is respectively connected with the output ends of the photovoltaic power generation system and/or the wind power generation system and is used for consuming and storing redundant electric quantity generated by the photovoltaic power generation system and/or the wind power generation system;

and the control system is connected with the energy storage system and is used for controlling the electric energy transmitted to the step-up transformer by the energy storage system according to the control signal sent by the electric quantity management system.

In addition, the invention also provides a new energy power generation direct drive system which is characterized by comprising an electric quantity management system, a booster transformer, a frequency converter, a first motor, a second motor, a gearbox, a control system, a photovoltaic power generation system and/or a wind power generation system;

the electric quantity management system is respectively connected with the photovoltaic power generation system and/or the wind power generation system and is used for adjusting electric energy management of the photovoltaic power generation system and the wind power generation system;

the output end of the photovoltaic power generation system and/or the output end of the wind power generation system are/is connected with the input end of a boosting transformer, and the output end of the boosting transformer is connected with the input end of a frequency converter;

the first motor is connected with the output end of the frequency converter, the second motor is driven by an external power grid, the first motor and the second motor are connected through the synchronous clutch, and the output end of the second motor is connected with an external load through the gearbox;

the control system is respectively connected with the electric quantity management system and the frequency converter and is used for controlling the output of the frequency converter according to the control signal sent by the electric quantity management system;

the first and second motors are started by:

s1, starting a second motor, disconnecting the first motor from the second motor, and starting the second motor;

s2, starting the first motor

S2.1, performing two-phase static coordinate conversion on three-phase stator current of the first motor to obtain corresponding current signals under a two-phase static transformation coordinate system, and performing two-phase rotation coordinate conversion to obtain corresponding current signals under a two-phase rotation coordinate system; the corresponding current signals under the two-phase rotating coordinate system are respectively exciting current and torque current;

s2.2, comparing the difference value of the exciting current and the torque current obtained in the step S1 with a preset exciting current and a preset torque current respectively, and outputting corresponding voltage signals after current regulation;

s2.3, carrying out reverse rotation transformation on the corresponding voltage signal output in the step S2, and converting the voltage signal into a corresponding voltage signal in a two-phase static transformation coordinate system;

s2.4, inputting the corresponding voltage signal under the two-phase static transformation coordinate system and the corresponding current signal under the two-phase static transformation coordinate system obtained in the step S1 into a rotor flux linkage observation and speed observation model, and using the obtained magnetic field orientation angle for the two-phase rotation coordinate conversion in the step S1;

meanwhile, inputting a corresponding voltage signal under the two-phase static transformation coordinate system into an inverter in a frequency converter for control, and further driving a first motor to start;

and S3, when the first motor is started to enable the rotating speed of the first motor to reach the rotating speed of the second motor through the step S2, the first motor and the second motor are connected through the synchronous clutch to enable the first motor and the second motor to coaxially run.

Further, in step S3, after the coaxially operating, the method further includes: the first motor is switched to torque loop control,

during the operation process that the first motor and the second motor coaxially operate to drive the external load together, the first motor and the second motor are controlled to synchronously operate according to the following method:

if the output power of the first motor changes:

when the frequency converter controls the first motor to increase the electromagnetic torque of the first motor, the slip of the second motor is reduced;

when the frequency converter controls the first motor to reduce the electromagnetic torque of the first motor, the slip of the second motor is increased;

if the output power of the second motor changes:

the rotating speeds of the first motor and the second motor are adjusted along with the power of the first motor, so that the first motor and the second motor operate at the same rotating speed.

Further, in step S2.2, after the current adjustment, the step of outputting the corresponding voltage signal further includes:

and after the preset exciting current and the preset torque current are subjected to feedforward compensation respectively, adding the difference comparison results corresponding to the preset exciting current and the preset torque current.

Further, the device also comprises a diesel generator;

the diesel generator is connected with the photovoltaic power generation system and/or the wind power generation system and used for supplying power to the photovoltaic power generation system and/or the wind power generation system before starting.

Further, the system also comprises an energy storage system;

the energy storage system is respectively connected with the output ends of the photovoltaic power generation system and/or the wind power generation system and is used for consuming and storing redundant electric quantity generated by the photovoltaic power generation system and/or the wind power generation system;

and the control system is connected with the energy storage system and is used for controlling the electric energy transmitted to the step-up transformer by the energy storage system according to the control signal sent by the electric quantity management system.

Compared with the prior art, the invention has the beneficial effects that:

1. the new energy power generation direct drive system solves the problem that loads of an isolated grid operation photovoltaic power generation and wind power generation direct drive system cannot continuously operate, a set of photovoltaic power generation and/or wind power generation distributed energy drive system is adopted for a region and users with nearby consumption where a large amount of photovoltaic power generation and/or wind power generation cannot be on line, a first motor driven by new energy such as photovoltaic power generation and/or wind power generation is added on the basis of an electric tractor set, and the first motor and a second motor jointly drag the loads, so that the problems that the users cannot be on line and cannot drag continuous operation loads due to new energy power generation are solved, green energy is utilized to the maximum extent, meanwhile, the use of large grid energy by enterprises at the peak of day electricity price is reduced, and the electricity consumption cost of the users is reduced.

The first motor decomposes the current to a dq axis through vector control to carry out decoupling control on the motor current so as to achieve a control effect similar to that of a direct current motor, realize real-time instruction tracking of a current torque component iq and a flux linkage component id and further realize accurate control of electromagnetic torque. After the second motor is started, the first motor achieves synchronous rotating speed with the second motor through vector control, then the two motors run coaxially through the synchronous clutch, the problem of synchronism control when the two motors powered by different power supplies drag the same load is successfully solved, and simulation experiments prove that the method is effective.

2. According to the invention, the energy storage system and the control system are configured, so that the whole new energy power generation direct drive system is more flexibly used, and the power output of the photovoltaic power generation system and/or the wind power generation system can be allocated according to the actual use requirement.

3. The control system can also control the output voltage of the frequency converter according to the control signal sent by the electric quantity management system, thereby further improving the flexibility of the system.

4. The method of the invention solves the problem that the motors powered by different power supplies have different influences on the motors due to different voltages, frequencies and power factors.

5. The method solves the problems of different rotating speeds and motor power distribution among motors powered by different power supplies.

6. The method solves the problem of shaft torsional vibration caused by different rotating speeds of the motors among the motors powered by different power supplies.

Drawings

FIG. 1 is a schematic diagram of a new energy power generation direct drive system according to a first embodiment of the invention;

FIG. 2 is a schematic diagram of a new energy power generation direct drive system according to a second embodiment of the invention;

fig. 3 is a schematic block diagram of a starting method of the first motor shown in fig. 1 and 2 according to the present invention.

The system comprises a photovoltaic power generation system 1, a wind power generation system 2, an energy storage system 3, a control system 4, an electric quantity management system 5, a step-up transformer 6, a frequency converter 7, a first motor 8, a second motor 9, a gear box 10, an external load 11, an external power grid 12 and a synchronous clutch 13.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments do not limit the present invention.

Example one

As shown in fig. 1, a new energy power generation direct drive system includes an electric quantity management system 5, a step-up transformer 6, a frequency converter 7, a first motor 8, a second motor 9, a gearbox 10, an energy storage system 3, a control system 4, a photovoltaic power generation system 1 and a wind power generation system 2.

The electric quantity management system 5 is respectively connected with the photovoltaic power generation system 1 and the wind power generation system 2, and is used for adjusting electric energy management of the photovoltaic power generation system 1 and/or the wind power generation system 2, so that the photovoltaic power generation system 1 and the wind power generation system 2 work according to preset parameter conditions. The output end of the photovoltaic power generation system 1 and the output end of the wind power generation system 2 are connected with the input end of a boosting transformer 6, the output end of the boosting transformer 6 is connected with the input end of a frequency converter 7, electricity generated by the photovoltaic power generation system 1 and the wind power generation system 2 is boosted to a voltage level of 35KV or higher through the boosting transformer 6, and then the electricity parameters are adjusted through the frequency converter 7 according to the actual needs of a first motor 8. The first motor 8 is connected with the output end of the frequency converter 7, the second motor 9 is driven by an external power grid 12 for supplying power, the first motor 8 and the second motor 9 are directly connected through a coupler, the output end of the second motor 9 is connected with an external load 11 through a gearbox 10, and in the embodiment, the external load 11 is a compressor.

The energy storage system 3 is respectively connected with the output ends of the photovoltaic power generation system 1 and the wind power generation system 2 and used for absorbing and storing redundant electric quantity generated by the photovoltaic power generation system 1 and the wind power generation system 2, so that the starting and running power of the new energy driving motor are enough, and the power supply quality of the photovoltaic power supply system is improved. The control system 4 is connected between the electric quantity management system 5 and the energy storage system 3, and is used for receiving the control signal sent by the electric quantity management system 5 and controlling the electric energy transmitted from the energy storage system 3 to the step-up transformer 6 according to the control signal, and the control system 4 is also connected with the frequency converter 7 and is used for controlling the output electric energy of the frequency converter 7 according to the control signal sent by the electric quantity management system 5. The electric quantity management system 5 is a remote control end of the whole new energy power generation direct drive system, and the work operation of the whole system is controlled through the control system 4.

The first motor 8 and the second motor 9 are directly connected through a coupler, and coaxially and operate at the same rotating speed, when the photovoltaic power generation system 1 and the wind power generation system 2 are insufficient in power generation, the first motor 8 operates as a load and a unit together, at the moment, the first motor 8 has certain mechanical loss which is within 1% of rated power of the motor, and the method is similar to the application of a small motor for dragging a large motor, in order to ensure that stable voltage and power output can be realized when the first motor 8 is started, the photovoltaic power generation system 1 and/or the wind power generation system 2 are/is provided with the energy storage system 3 at a power station side, and a diesel generator can be arranged in a corresponding power distribution system, so that the diesel generator is connected with the photovoltaic power generation system 1, the wind power generation system 2 and the step-up transformer 6 and used for supplying power for the power supply before the photovoltaic power generation system 1 and the wind power generation system 2 are started. The second motor 9 is powered by an external power grid 12 and operates at power frequency, the first motor 8 is controlled by frequency conversion, the purpose of driving an external load 11 coaxially with the second motor 9 is achieved, and the second motor 9 powered by the external power grid 12 and the first motor 8 powered by the photovoltaic power generation system 1 and the wind power generation system 2 reliably operate at the same rotating speed.

The first embodiment of the invention is more suitable for newly-built photovoltaic power generation systems 1 and/or wind power generation systems 2 which can not be operated in a grid-connected mode with a power frequency power grid due to policy reasons and have nearby consumption conditions, or existing power stations which are built on the Internet and have consumption conditions but still have the phenomenon of abandoning wind and light.

Example two

As shown in fig. 2, the difference from the first embodiment of the present invention is that the first electric machine 8 and the second electric machine 9 are not directly connected by a coupling, but are connected by a synchronizer clutch 13.

The rotating speeds of the first motor 8 and the second motor 9 are matched, a synchronous clutch is adopted for connection, when the rotating speed of the first motor 8 is larger than or equal to that of the second motor 9, instant input of the first motor 8 can be achieved, when the power generation energy of the photovoltaic power generation system 1 and/or the wind power generation system 2 is insufficient, the synchronous clutch 13 automatically cuts off the first motor 8, reliable operation of dragging load of the second motor 9 is guaranteed, similarly, in order to achieve stable voltage and power output when the first motor 8 is started, the photovoltaic power generation system 1 and/or the wind power generation system 2 can be provided with the energy storage system 3 on the side of a power station, and a diesel generator is arranged in a corresponding power distribution system.

The second motor 9 is powered by an external power grid 12 and operates at power frequency, the first motor 8 is controlled by frequency conversion, the purpose of driving an external load 11 coaxially with the second motor 9 is achieved, and the second motor 9 powered by the external power grid 12 and the first motor 8 can operate reliably at the same rotating speed.

The invention has passed the technical simulation verification, the simulation result proves the feasible scheme of the invention.

In addition, in another embodiment of the present invention, the photovoltaic power generation system 1 and the wind power generation system 2 in the first embodiment and the second embodiment of the present invention may be replaced with a single photovoltaic power generation system 1 or wind power generation system 2. The photovoltaic power generation system 1 and/or the wind power generation system 2 can be replaced by other new energy power generation systems, the problem that the other new energy power generation systems cannot continuously drive loads to work similarly can be solved, or the power supply efficiency of the other new energy power generation systems can be improved.

In addition, the electric quantity management system 5, the control system 4 and the energy storage system 3 in the invention can adopt the existing corresponding systems commonly used in the existing power station system, wherein the configured corresponding software is also a mature existing program and can be directly configured for use, and the innovation of the invention is not.

In addition, because the voltage, frequency and other network parameters of the two power supplies are different, the rotating speeds of the two motors are inconsistent, and when the same load is dragged, shaft torque is generated, so that the unit is in failure, and the unit cannot normally operate.

In the first and second embodiments of the present invention, the input of the frequency converter 7 can be both phase-shifting transformer, and the secondary side is step-down and is in the form of extended triangle. The three-phase input of each power unit is rectified by a rectifier bridge and filtered by a capacitor to become stable direct current, then is inverted into single-phase SPWM waveform by an H bridge consisting of IGBTs, each phase is formed by connecting a plurality of power units in series, and the output is connected to form a high-voltage system to directly drive the second motor 2. When two motors powered by different power supplies coaxially drag the same external load 11, the instantaneous voltage and frequency of the power supplies of the two motors may be different, which results in the conditions that the rotating speeds of the two motors are asynchronous, the shafting generates torsional vibration, the motors are overloaded, and the like. In order to avoid this, the present invention also proposes a synchronization control method as follows:

when the motor is started, the second motor 9 is started first, then the first motor 8 which is controlled to operate by the variable-frequency torque ring is started, when the first motor 8 is started, the problem of coaxial driving of the two motors is considered, the motor can be rotated to track and start, and the first motor 8 is dragged. Before the first motor 8 runs coaxially with the second motor 9 through the synchronous clutch 6, the first motor 8 needs to be started through the frequency converter 7, so that the rotating speed of the first motor 8 is basically consistent with that of the second motor 9, and at the stage, the frequency converter 7 controls the first motor 8 to run by adopting a speed-sensor-free vector control strategy shown in fig. 3. According to the vector control principle of the asynchronous motor, the current is decomposed to a dq axis to decouple and control the current of the asynchronous motor, so that the control effect similar to that of a direct current motor is achieved, real-time instruction tracking of a current torque component iq and a flux linkage component id is achieved, and accurate control of electromagnetic torque is achieved.

Vector control of the start of the first electric machine 8 includes closed-loop control of the rotational speed and closed-loop control of the stator current. Preset rotor speedAnd the actual rotor speed omega obtained by identification_rPerforming a difference comparisonOutput torque current after passing through PI speed regulatorThe difference value of the preset rotor flux linkage and the actual rotor flux linkage obtained by the rotor flux linkage observation and speed observation model is compared, and the excitation current is output through the flux linkage regulatorNamely the preset exciting current. The stator current of the first electric machine 8 can be measured by means of a current transformer, the voltage is obtained by means of a voltage reconstruction technique, and the current signal (i) obtained_A、i_B、i_C) After three-phase static to two-phase static coordinate transformation (3s/2s transformation), obtaining a corresponding current signal i under a two-phase static transformation coordinate system_sα、i_sβThe current signal is used as the current input for rotor flux linkage observation and speed observation for calculating the rotor flux linkage and the magnetic field orientation angle theta, and meanwhile, the current signal is subjected to PARK transformation (transformation from two-phase stationary to two-phase rotating coordinates) to obtain a corresponding current signal under a two-phase rotating coordinate systemExciting current on two-phase rotating coordinate system dqTorque currentRespectively with a predetermined exciting currentPreset torque currentInputting the current regulator after difference operation, respectively performing feedforward compensation on the preset exciting current and the preset torque current, adding the sum of the difference comparison results and the corresponding difference comparison results, and outputting the sum on a dq shaftingVoltage signalThen converted into voltage on two-phase stationary coordinate system alpha beta by inverse PARKThe voltage is used as the input of a model for calculating the rotor flux linkage observation and speed observation, and the VSI is controlled at the same time, so that the first motor 8 is driven to operate.

The vector control is based on the realization of real-time instruction tracking of the current torque component iq and the flux linkage component id, so that the accurate control of the electromagnetic torque is realized.

After the first motor 8 and the second motor 9 reach synchronous rotating speed, the synchronous clutch 6 switches the first motor 8 and the second motor 9 to coaxial operation, the rotating speed loop control started by the first motor 8 can be cut off, a torque loop vector control mode is adopted, and the control method after switching is as follows:

after the first motor 8 and the second motor 9 coaxially operate, the first motor 8 adopts a maximum power operation vector control mode, the first motor 8 and the second motor 9 coaxially drive the load 5 according to the power output of the photovoltaic power generation system and/or the wind power generation system, in the process, the first motor 8 and the second motor 9 need to operate at the same rotating speed and the same frequency, and a power equation and a torque equation of the system are respectively as follows:

P_{first motor}+P_{Second electric machine}＝P_Load(s)

Wherein, P_{First motor}Is the output power of the first motor, P_{Second electric machine}Is the output power of the second motor, P_Load(s)Is the power of the load, T_{First motor}Is the output torque of the first electric machine, T_{Second electric machine}Is the output torque of the second electric machine, T_Load(s)Is the torque of the load, J is the system moment of inertia,is the system acceleration.

The difference between the output torque of the second motor 9 and the output torque of the first motor 8 controlled by the frequency converter 7 and the torque of the load 5 determines the rotation speed variation and the synchronism control of the system. When the frequency converter 7 is changed according to the available energy of the photovoltaic power generation system and/or the wind power generation system, the output power is also changed. When the frequency converter 7 controls the first motor 8 to output a larger electromagnetic torque according to the increased active power instruction, the acceleration of the system is positive, the system is accelerated to run, so that the slip of the second motor 9 is reduced, the output electromagnetic torque is also reduced, and the torque equation of the system is rebalanced; when the frequency converter 7 controls the electromagnetic torque output by the first motor 8 to be reduced according to the active power reduction command, the adjustment process of the system electromagnetic torque equation is just opposite to the process, so that the system reaches new balance.

When the output power of the second motor 9 changes to bring the slip of the second motor 9 into change, the rotating speed is changed along with the fluctuation of the power output of the first motor 8, so that the second motor 9 and the first motor 8 run coaxially and at the same rotating speed, and the running rotating speed of the system is changed between the rated load rotating speed and the no-load rotating speed of the second motor 9.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to other related technical fields, are included in the scope of the present invention.