阅读说明：本技术 功率因数校正的电流锁相环控制方法及电机控制系统 (Power factor correction current phase-locked loop control method and motor control system ) 是由 周广旭 慕永云 马建辉 朱孟美 宋宁冉 郭磊 刘婷婷 王天佑 于 2021-07-01 设计创作，主要内容包括：本发明公开了一种功率因数校正的电流锁相环控制方法及电机控制系统,包括：获取交流侧电源的电压过零点信号后,根据预设的功率器件开关频率得到锁相环同步脉冲数；根据锁相环同步脉冲数、锁相环中断周期和电机绕组目标电流采用正弦脉宽调制法控制功率器件在每个锁相环中断周期的导通和导通时间,以使电源输出给电机供电的正弦波电流。基于功率因数校正,对电机电流的斩波控制,使输入侧电源电流按正弦波变化输出,以对电机供电,保证电机正常运转的同时提高功率因数。(The invention discloses a current phase-locked loop control method and a motor control system for power factor correction, which comprise the following steps: after a voltage zero crossing point signal of an alternating current side power supply is obtained, the synchronous pulse number of a phase-locked loop is obtained according to a preset switching frequency of a power device; and controlling the conduction and conduction time of the power device in each phase-locked loop interrupt period by adopting a sine pulse width modulation method according to the synchronous pulse number of the phase-locked loop, the phase-locked loop interrupt period and the motor winding target current so that the power supply outputs sine wave current for supplying power to the motor. Based on power factor correction, the current of the motor is subjected to chopping control, so that the power supply current at the input side is output according to the change of a sine wave to supply power to the motor, and the power factor is improved while the normal operation of the motor is ensured.)

1. A power factor corrected current phase locked loop control method is characterized by comprising the following steps:

after a voltage zero crossing point signal of an alternating current side power supply is obtained, the synchronous pulse number of a phase-locked loop is obtained according to a preset switching frequency of a power device;

and controlling the conduction and conduction time of the power device in each phase-locked loop interrupt period by adopting a sine pulse width modulation method according to the synchronous pulse number of the phase-locked loop, the phase-locked loop interrupt period and the motor winding target current so that the power supply outputs sine wave current for supplying power to the motor.

2. The method as claimed in claim 1, wherein the power device comprises a first power device, a second power device, and a third power device, the first power device is turned on first, and if the current output by the power supply is greater than the target current of the motor winding after the first power device is turned on, the residual current is charged to the energy storage capacitor.

3. The method as claimed in claim 2, wherein if the current output from the power supply is smaller than the target current of the motor winding after the first power device is turned on, the second power device is controlled to be turned on to supply power to the energy storage capacitor.

4. The method of claim 2, wherein the third power device is always on, and the third power device is controlled to turn off when the current output by the power supply is greater than the target current of the motor winding.

5. A power factor corrected current phase locked loop control method as claimed in claim 1, wherein the modulation process of the sinusoidal pulse width modulation method is:wherein T is the phase-locked loop interrupt period; t is_iFor conducting power devices during each PLL interrupt periodThe on time; m is a modulation depth coefficient; i is 1-N, counting controlled by the phase-locked loop; and N is the synchronous pulse number of the phase-locked loop.

6. A power factor corrected current phase locked loop control method as claimed in claim 1, wherein the number of phase locked loop synchronization pulses increases with an increase in the switching frequency of the power device.

7. A motor controller, comprising:

the pulse acquisition unit is configured to acquire a voltage zero crossing point signal of a power supply and then obtain the synchronous pulse number of the phase-locked loop according to a preset switching frequency of a power device;

and the modulation unit is configured to control the conduction and conduction time of the power device in each phase-locked loop interrupt period by adopting a sine pulse width modulation method according to the phase-locked loop synchronous pulse number, the phase-locked loop interrupt period and the motor winding target current so that the power supply outputs sine wave current for supplying power to the motor.

8. A motor control system, comprising: a motor, a power source, and the motor controller of claim 7; the motor controller controls the sine wave current output by the power supply to power the motor by using the control method of any one of claims 1-6.

9. A motor control system as claimed in claim 8, further comprising an energy storage capacitor for storing residual current after the power device is turned on.

10. A motor control system as claimed in claim 9 wherein the energy storage capacitor is arranged to provide current to the motor when the current from the power supply is insufficient to meet the current demand from the motor windings.

Technical Field

The invention relates to the technical field of motor control, in particular to a current phase-locked loop control method for power factor correction and a motor control system.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

According to the current requirements of environmental protection and energy saving, a high power factor is required on the input side of electric equipment, an uncontrollable rectifying circuit is generally adopted on the input side of the existing motor controller, so that the power factor of a system is too low, active power factor correction refers to that the input power factor is improved through an active circuit (an active circuit), and a switching device is controlled to enable an input current waveform to follow an input voltage waveform, so that the high power factor is realized. In order to achieve unity power factor, it is now conventional to achieve an increase in power factor by a separate power factor correction circuit. However, the method can increase the size of the controller and the cost of the system, has insignificant competitive advantages, and particularly causes the problem of higher cost than other types of motors in low-power application occasions.

Disclosure of Invention

In order to solve the problems, the invention provides a current phase-locked loop control method for power factor correction and a motor control system, which realize power factor correction and chopping control on motor current, so that the power supply current at the input side is output according to sine wave change to supply power to a motor, thereby ensuring the normal operation of the motor and simultaneously improving the power factor of the system.

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

in a first aspect, the present invention provides a method for controlling a power factor corrected current phase-locked loop, including:

after a voltage zero crossing point signal of an alternating current side power supply is obtained, the synchronous pulse number of a phase-locked loop is obtained according to a preset switching frequency of a power device;

and controlling the conduction and conduction time of the power device in each phase-locked loop interrupt period by adopting a sine pulse width modulation method according to the synchronous pulse number of the phase-locked loop, the phase-locked loop interrupt period and the motor winding target current so that the power supply outputs sine wave current for supplying power to the motor.

As an alternative implementation manner, the power device includes a first power device, a second power device, and a third power device, where the first power device is turned on first, and if the current output by the power supply is greater than the target current of the motor winding after the first power device is turned on, the residual current is used to charge the energy storage capacitor.

As an alternative implementation manner, if the current output by the power supply is smaller than the target current of the motor winding after the first power device is turned on, the second power device is controlled to be turned on, and the energy storage capacitor supplies power.

In an alternative embodiment, the third power device is always on, and when the current output by the power supply is larger than the target current of the motor winding, the third power device is controlled to be off.

As an alternative embodiment, the modulation process of the sine pulse width modulation method is as follows:wherein T is the phase-locked loop interrupt period; t is_iThe conducting time of the power device in each phase-locked loop interrupt period is set; m is a modulation depth coefficient; i is 1-N, counting controlled by the phase-locked loop; and N is the synchronous pulse number of the phase-locked loop.

As an alternative embodiment, the number of phase locked loop synchronization pulses increases with increasing switching frequency of the power device.

In a second aspect, the present invention provides a motor controller comprising:

the pulse acquisition unit is configured to acquire a voltage zero crossing point signal of a power supply and then obtain the synchronous pulse number of the phase-locked loop according to a preset switching frequency of a power device;

and the modulation unit is configured to control the conduction and conduction time of the power device in each phase-locked loop interrupt period by adopting a sine pulse width modulation method according to the phase-locked loop synchronous pulse number, the phase-locked loop interrupt period and the motor winding target current so that the power supply outputs sine wave current for supplying power to the motor.

In a third aspect, the present invention provides a motor control system, including: a motor, a power supply and the motor controller of the second aspect; the motor controller controls the power supply to output sine wave current for supplying power to the motor by adopting the control method of the first aspect.

In an alternative embodiment, the system further comprises an energy storage capacitor, and the energy storage capacitor is used for storing residual current after the power device is turned on.

In an alternative embodiment, the energy storage capacitor is used for supplying current for the motor to run when the current output by the power supply is insufficient to meet the current requirement of the motor winding.

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

the current phase-locked loop based on the active power factor has a simple control algorithm, controls the output of current according to the operation requirement of the motor, realizes the sinusoidal change of the current on the input side, and simultaneously realizes the unit power factor on the input side.

And controlling the conduction and conduction time of the power device in each phase-locked loop interrupt period by adopting a sine pulse width modulation method according to the synchronous pulse number of the phase-locked loop, the phase-locked loop interrupt period and the motor winding target current. In the method, acquisition of phase-locked loop synchronous pulses, control of an interruption period and sine pulse width modulation of motor winding current are all realized by software, and finally, power factor adjustment can be realized by controlling a power device of the conventional motor without additionally and independently configuring a power factor adjustment circuit, so that the volume and the system cost of a controller are reduced.

When the current of power output satisfies the required current of motor winding, with the residual current storage to the electric capacity in to when the current of power output can't satisfy the required current of motor winding, can pass through the electric capacity power supply, effectively utilize power energy and capacitive energy, the operating efficiency is higher.

Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

Fig. 1 is a flowchart of a power factor corrected current phase locked loop control method according to embodiment 1 of the present invention;

fig. 2 is a timing chart of input side current control provided in embodiment 1 of the present invention;

fig. 3 is a timing chart of the motor winding current control provided in embodiment 1 of the present invention;

fig. 4 is a topology structure diagram of a switched reluctance motor controller with integrated Active Power Factor Correction (APFC) according to embodiment 3 of the present invention;

the system comprises an alternating current-direct current conversion circuit 1, a power conversion circuit 2, an energy storage capacitor 3, a zero-crossing detection circuit 4, a power supply detection circuit 5, an isolation driving circuit 6, a motor detection circuit 7, a capacitor detection circuit 8, a display circuit 9 and a processor 10.

The specific implementation mode is as follows:

the invention is further described with reference to the following figures and examples.

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and it should be understood that the terms "comprises" and "comprising", and any variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

Example 1

As shown in fig. 1, the present embodiment provides a current phase-locked loop control method based on active power factor correction, including:

s1: after a voltage zero crossing point signal of an alternating current side power supply is obtained, the synchronous pulse number of a phase-locked loop is obtained according to a preset switching frequency of a power device;

s2: and controlling the conduction and conduction time of the power device in each phase-locked loop interrupt period by adopting a sine pulse width modulation method according to the synchronous pulse number of the phase-locked loop, the phase-locked loop interrupt period and the motor winding target current so that the power supply outputs sine wave current for supplying power to the motor.

In step S1, after the voltage zero crossing point of the input-side ac power supply is detected according to the current zero crossing point, a phase-locked loop signal is calculated, so as to implement synchronous control of voltage and current;

in this embodiment, taking a positive half cycle of an ac side voltage of 50hz (cycle 20ms) as an example, when a switching frequency of a power device is 10khz, N is 10000/(1000/10) ═ 100 synchronization pulses in a half cycle T/2 after a zero crossing point is 10 ms;

when the switching frequency of the power device is 20khz, the number of the synchronization pulses is 10000/(1000/20) ═ 200.

Preferably, the number of the synchronization pulses of the phase-locked loop is adjusted along with the adjustment of the switching frequency of the power device, and is increased along with the increase of the switching frequency.

In the step S2, the power devices include a first power device Q1, a second power device Q2 and a third power device Q3, and the target current i of the motor winding is obtained according to the motor operation command_mThe motor does not need current in the phase-locked pulse before the ON angle of the motor and the phase-locked pulse after the OFF angle of the motor; in the angle from ON to OFF of the motor, according to the target current of the motor winding, a first power device Q1 is firstly conducted, the first power device Q1 controls the output of the current ON the alternating current side according to PWM control logic, the current ON the alternating current power supply side output by the first power device in a conduction mode is used for charging the motor winding, and a third power device Q3 is always conducted to realize the continuation of the energy of the motor winding; as shown in fig. 2-3, the control timing diagrams of the input side current and the motor winding current are respectively;

namely, a driving pulse width modulation signal of the first power device Q1 is modulated by adopting Sinusoidal Pulse Width Modulation (SPWM) to control the conduction of the first power device Q1, so that the sinusoidal wave change of the current at the front end of the first power device Q1 after the zero crossing point is realized;

wherein, the output alternating side current is:i＝1～N。

preferably, the modulation process is:

wherein, T is an interrupt period controlled by each phase-locked loop; t is_iFor the on-time of Q1 in each interrupt period; m is a modulation depth coefficient and is modulated according to the current of the motor winding; i is 1-N, counting controlled by the phase-locked loop; and N is the synchronous pulse number of the phase-locked loop.

In this embodiment, if i_m>i_siWhen the alternating current side current of the first power device Q1 after being conducted is smaller than the target current of the motor winding, the first power device Q1 is conducted, and meanwhile, the second power device Q2 is controlled to be conducted, and the energy storage capacitor supplies power to the motor; namely:

i_m＝i_s+i_c

T_m＝T_i+T_c

wherein, T_iFor the on-time of Q1 in each interrupt period; t is_mThe conduction time of the Q1 to the motor current in each interrupt period; t is_cFor the on-time of Q2 in each interrupt period; i.e. i_cIs the capacitive current.

If i_m<i_siWhen the first power device Q1 is switched on, the alternating current side current is larger than the motor winding target current, and the alternating current side current can meet the motor winding target current, the third power device Q3 is controlled to be switched off while the first power device Q1 is switched on, and the redundant capacity of the power supply charges the energy storage capacitor through the power diode D5; namely:

i_m＝i_s-i_c

T_c＝T_m-T_i

i_s＝i_s(sinωt)

wherein, T_iFor the on-time of Q1 in each interrupt period; t is_mThe conduction time of the Q1 to the motor current in each interrupt period; t is_cIs the on time of Q2 for each interrupt period.

Example 2

The present embodiment provides a motor controller including:

the pulse acquisition unit is configured to acquire a voltage zero crossing point signal of a power supply and then obtain the synchronous pulse number of the phase-locked loop according to a preset switching frequency of a power device;

and the modulation unit is configured to control the conduction and conduction time of the power device in each phase-locked loop interrupt period by adopting a sine pulse width modulation method according to the phase-locked loop synchronous pulse number, the phase-locked loop interrupt period and the motor winding target current so that the power supply outputs sine wave current for supplying power to the motor.

It should be noted that the modules correspond to the steps described in embodiment 1, and the modules are the same as the corresponding steps in the implementation examples and application scenarios, but are not limited to the disclosure in embodiment 1. It should be noted that the modules described above as part of a system may be implemented in a computer system such as a set of computer-executable instructions.

Example 3

As shown in fig. 4, the present embodiment provides a motor control system including: a motor, a power supply and a motor controller as described in embodiment 2; the motor controller controls the sine wave current output by the power supply to supply power to the motor by adopting the control method described in embodiment 1.

In the present embodiment, the dc-ac conversion circuit 1 is further included, and is configured to convert an ac power into a dc power;

in the positive half cycle of the power supply, D1 and D4 are switched on, D2 and D3 are switched off, and the current returns to the lower end of the power supply from the upper end of the power supply through D1 → Q1 → D4;

in the negative half cycle of the power supply, D1 and D4 are turned off, D2 and D3 are turned on, and the current returns from the lower end of the power supply to the upper end of the power supply through D3 → RL → D2.

In the present embodiment, a power supply side power supply detection circuit 5 is further included for detecting the ac side power supply voltage and current to facilitate the calculation of the input side power by the motor controller.

In the present embodiment, a zero-crossing detection circuit 4 on the power supply side is further included, which is used for detecting a voltage zero-crossing signal of the ac power supply according to the detection of the power supply voltage and current, so as to realize the synchronous control of the voltage and the current.

In the present embodiment, the motor side includes a power conversion circuit 2, the power conversion circuit 2 includes power devices Q1, Q2, Q3, power diodes D5, D6, D7; after the voltage zero crossing point is detected, the conduction time of the power device is controlled according to the comparison between the target current of the winding of the switched reluctance motor and the alternating current after the power device is conducted, so that the alternating current and the capacitor supply power to the motor, the normal operation of the motor is ensured, and the power factor correction of the power source side is realized.

In this embodiment, the motor detection circuit 7 on the motor side is further included, and is used for detecting the motor current and the rotor position in real time, so as to control the conduction phase sequence of the motor winding and the motor current.

In this embodiment, the power supply further includes an energy storage capacitor 3, configured to store a residual current after the power device is turned on, and configured to provide energy to the motor winding to charge the motor when an alternating current side current is not enough to meet a current required by the motor winding.

In the embodiment, the capacitance detection circuit 8 on the energy storage capacitor side is included, and is used for detecting the voltage and the current of the capacitor so as to calculate the input and output power of the capacitor and the state of charge stored by the capacitor in real time.

In this embodiment, the device further includes a display circuit 9, configured to display the key operating parameters and set the parameters through a keyboard.

In this embodiment, the power conversion circuit further includes an isolation driving circuit 6, which is used for isolating, amplifying, etc. the control signal, so as to control the power device in the power conversion circuit.

In this embodiment, the processor includes a digital input circuit, a pulse width adjusting circuit, an analog-to-digital conversion circuit, and a digital output circuit;

the digital quantity input circuit is used for processing digital quantity signals input to the control system, such as input of a key and input of a relay node;

and the pulse width adjusting circuit is used for processing such as driving amplification, isolation and the like of the pulse width signal output by the processor.

The analog-to-digital conversion circuit is used for processing analog quantity such as motor current and obtaining a digital quantity signal through the processor.

A digital quantity output circuit; the digital quantity signal processing method is used for processing the digital quantity signal output by the processor, such as controlling relay actuation and the like in a system.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.