A power double compensation switched reluctance motor drive system and control method

Abstract

The present invention discloses a power dual-compensation switched reluctance motor drive system and control method, including: an active power compensation circuit for absorbing DC bus pulsating power to achieve primary power compensation; a primary power compensation circuit control module for driving and controlling the primary side active power compensation circuit; a switched reluctance motor power main circuit for driving the switched reluctance motor; and a secondary power compensation control module for generating a compensation signal to drive and control the switched reluctance motor power main circuit to achieve secondary power compensation. The present invention can achieve that when a small-capacity film capacitor is used to replace a large-capacity electrolytic capacitor in a switched reluctance motor drive system, the motor can still effectively and stably output power, and the control method is simple and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of switched reluctance motor drive systems, and in particular to a power double-compensated switched reluctance motor drive system and a control method. Background Art

[0002] The switched reluctance motor itself has simple and solid structure, no permanent magnets, and no rotor windings, which allows it to operate under harsh working conditions and has high reliability, making it widely used in various fields such as household appliances, power tools, electric vehicles, aerospace, etc. A large electrolytic capacitor is generally connected in parallel to the DC bus of the switched reluctance motor drive system. Due to the characteristics of the electrolytic capacitor itself, its life and reliability are greatly affected by ripple current, equivalent series resistance, ambient temperature, etc., which in turn affects the reliability and life of the entire system, becoming the short board of the life and reliability of the switched reluctance motor drive system. Therefore, it is of great research significance to use smaller film capacitors to replace traditional large-capacity electrolytic capacitors.

[0003] Directly replacing large-capacity electrolytic capacitors with small-capacity film capacitors without changing the rest of the circuit topology and control method will result in poor system stability. The DC bus voltage after rectification fluctuates greatly with load changes, which in turn causes large fluctuations in the motor output power. This is only suitable for applications with very small loads such as fans. The existence of its pulsating output power greatly limits the performance of the motor and also limits its application in scenarios with certain requirements for load torque.

[0004] When the active power compensation circuit is used alone as the output power compensation of the switched reluctance motor drive system, under the condition that the output power requirement is close to kilowatts or even several kilowatts and the DC bus is only connected in parallel with a small film capacitor, the DC bus voltage ripple will increase with the increase of load and cannot maintain a small DC bus voltage ripple; when the dynamic adjustment of the motor winding voltage is used alone to achieve output power compensation, when the DC bus voltage is low, the adjustment of the winding voltage is greatly restricted, and it is difficult to achieve compensation for the motor output power pulsation. Summary of the invention

[0005] Purpose of the invention: In view of the above technical problems, the present invention provides a power double compensation type switch reluctance motor drive system. On the basis of using small-capacity film capacitors to replace large-capacity electrolytic capacitors, the output power of the switch reluctance motor drive system without electrolytic capacitors can be effectively stabilized by adopting a double power compensation structure, which largely solves the problem of large motor output power pulsation in the small-capacitor switch reluctance motor drive system. At the same time, by setting a control method for the power double compensation type switch reluctance motor drive system, the reliability and life of the drive system are improved.

[0006] Technical solution: To solve the above problems, the present invention discloses a power dual-compensation switched reluctance motor drive system, which specifically includes: a primary compensation circuit and a control part, a secondary compensation circuit and a control part; the primary compensation circuit and the control part include: an AC power supply, a rectifier bridge, a first film capacitor, an active power compensation circuit, and a primary power compensation control module; the secondary compensation circuit and the control part include a switched reluctance motor power main circuit, a switched reluctance motor, a position detection module, and a secondary power compensation control module;

[0007] The AC power supply is a single-phase sinusoidal AC power supply, and both ends of the AC power supply are connected to the AC input ends of the rectifier bridge to provide single-phase sinusoidal AC power to the rectifier bridge; the rectifier bridge is used to rectify the input single-phase sinusoidal AC power into DC power and supply power to the active power compensation circuit; the active power compensation circuit connected in parallel with the rectifier bridge is a bidirectional DC-DC converter, which is used to absorb the power pulsation at the DC output end of the rectifier bridge; the primary power compensation control module is used to generate a primary power compensation signal according to the AC bus voltage output by the AC power supply collected in real time and convert it into a PWM signal with a corresponding duty cycle to drive the active power compensation circuit;

[0008] The first film capacitor is connected in parallel between the active power compensation circuit and the switched reluctance motor power main circuit, and is used to stabilize the voltage at the input end of the switched reluctance motor power main circuit;

[0009] The position detection module is used to detect the rotor position of the switched reluctance motor and send the rotor position signal to the secondary power compensation control module; the secondary power compensation control module is used to generate a secondary power compensation signal based on the error value between the DC bus voltage output by the active power compensation circuit and the reference voltage collected in real time, and combine the rotor position signal and the secondary power compensation signal to form a switch drive control signal that is transmitted to the switched reluctance motor power main circuit; the switched reluctance motor power main circuit is used to receive the switch tube drive control signal and control the switched reluctance motor according to the switch tube drive control signal.

[0010] Furthermore, the bidirectional DC-DC converter has a second film capacitor for absorbing or releasing converter energy; the primary power compensation control module specifically includes: an AC side voltage acquisition module, a first signal modulation module, a first summing module, a first voltage limiting module, a PWM signal generator, a first voltage acquisition module, a first reference voltage module, a first difference module, and a closed-loop regulator module;

[0011] The AC side voltage acquisition module is used to acquire the sinusoidal voltage signal of the AC power supply and transmit it to the first signal modulation module; the first signal modulation module is used to modulate the sinusoidal voltage signal output by the AC side voltage acquisition module into a primary power compensation signal, and transmit it to the first summing module; the first voltage acquisition module is used to acquire the voltage signal at both ends of the second film capacitor and transmit it to the first difference module; the first reference voltage module is used to generate a first reference voltage and transmit it to the first difference module; the first difference module is used to differ the voltage signal at both ends of the second film capacitor from the first reference voltage, and transmit the error signal obtained by the difference to the closed-loop regulator module; the closed-loop regulator module is used to adjust and correct the error signal output by the difference module and transmit it to the first summing module; the first summing module is used to sum the signal transmitted to the first summing module and transmit the summing result to the first voltage limiting module; the first voltage limiting module is used to limit the amplitude of the output signal of the first summing module and transmit it to the PWM signal generator; the PWM signal generator is used to convert the output signal of the first voltage limiting module into a PWM signal with a corresponding duty cycle.

[0012] Furthermore, the secondary power compensation control module specifically includes a microcontroller, a second limiting module, a second signal modulation module, a second difference module, a second voltage acquisition module, and a second reference voltage module;

[0013] The second voltage acquisition module is used to acquire the DC bus voltage output by the active power compensation circuit in real time and transmit it to the second differential module; the second reference voltage module is used to generate a second reference voltage and transmit it to the second differential module; the second differential module is used to differentiate the output signal of the second voltage acquisition module and the output signal of the second reference voltage module and transmit it to the second signal modulation module; the second signal modulation module is used to modulate the output signal of the second summation module into a secondary power compensation signal and transmit it to the second limiting module; the second limiting module is used to limit the amplitude of the output signal of the second signal modulation module and transmit it to the microcontroller; the microcontroller is used to form a switch tube drive control signal in the power main circuit of the switched reluctance motor according to the rotor position signal and the signal output by the second limiting module.

[0014] Furthermore, the bidirectional DC-DC converter is a boost type DC-DC bidirectional converter, which specifically includes an inductor, a first gate switch tube, a second gate switch tube, an inversion module, and a second film capacitor;

[0015] One end of the inductor is connected to the positive rectifier output terminal of the rectifier bridge, and the other end of the inductor is respectively connected to the drain of the first selection switch tube and the source of the second selection switch tube; the source of the first selection switch tube is connected to the negative rectifier output terminal of the rectifier bridge; the gate of the first selection switch tube and the input end of the inversion module are both connected to the output end of the PWM signal generator; the output end of the inversion module is connected to the gate of the second selection switch tube, the drain of the second selection switch tube is connected to one end of the second film capacitor, and the other end of the second film capacitor is connected to the negative rectifier output terminal of the rectifier bridge; the first selection switch tube and the second selection switch tube are both power switch tubes with anti-parallel diodes.

[0016] Furthermore, the first signal modulation module includes a multiplier module and a first proportional module; the multiplier module is used to perform a square operation on the AC voltage signal output by the AC side voltage acquisition module and transmit it to the first proportional module; the first proportional module is used to perform a proportional transformation on the amplitude of the multiplier output signal and transmit it to the first summation module.

[0017] Furthermore, the primary power compensation control module also includes a bias voltage module and a first judgment module; the first judgment module is used to judge the output signal of the first difference module and select it for transmission to the closed-loop regulator module; the bias voltage module is used to generate a bias voltage and output it to the first summation module.

[0018] Furthermore, the closed-loop regulator module is a PI module or a module used to perform closed-loop regulation on the error signal output by the first difference module; when the closed-loop regulator module selects the PI module, the PI module performs PI regulation on the output signal of the first judgment module and transmits it to the first summation module.

[0019] Furthermore, the switched reluctance motor power main circuit is an N-phase asymmetric half-bridge circuit, where N is a positive integer greater than 2.

[0020] Furthermore, the second signal modulation module specifically includes a second judgment module and a second proportional module; the second judgment module is used to judge the output signal of the second difference module and select it for transmission to the second proportional module; the second proportional module is used to proportionally transform the amplitude of the output signal of the second judgment module and transmit it to the second limiting module.

[0021] In addition, the present invention also provides a control method for a power double-compensation switched reluctance motor drive system, comprising the following steps:

[0022] (1) Setting the amplitude conversion ratio of the first proportional module in the primary power compensation control module, setting the preset value of the bias voltage, setting the judgment logic of the first judgment module, and setting the preset value of the first reference voltage; according to the voltage v collected in real time by the AC side voltage collection module ac, the voltage v across the second film capacitor collected in real time by the first voltage collection module C2 Get the final generated PWM signal;

[0023] The amplitude conversion ratio conversion formula of the first proportional module is specifically:

[0024]

[0025] In the formula, v in is the multiplier output signal; x in is the primary power compensation signal output by the first proportional module; v c2max is the upper limit of the voltage of the second film capacitor, v c2min is the lower limit of the voltage of the second film capacitor; V DC is the average voltage of the DC bus, v acmax is the maximum value of AC bus voltage;

[0026] The specific formula for the preset value of the bias voltage is:

[0027]

[0028] In the formula, v BB is the bias voltage signal; D min The active power compensation circuit driving signal s BB The minimum duty cycle value of

[0029] The specific formula of the judgment logic of the first judgment module is:

[0030]

[0031] Wherein, Δv1 is the output signal of the first difference module; Δv1' is the output signal of the first judgment module; V ref1 is a first reference voltage;

[0032] The first reference voltage V ref1 The specific formula for the preset value is:

[0033] V ref1 =(0.3~0.5)V CN

[0034] Where V CN is the nominal rated voltage value of capacitor C2;

[0035] (2) setting the amplitude conversion ratio of the second proportional module in the secondary power compensation control module, setting the judgment logic of the second judgment module, and setting the preset value of the second reference voltage; according to the DC bus voltage v output by the active power compensation circuit collected in real time by the second voltage collection module DCObtain the switch tube drive control signal output by the microprocessor;

[0036] The judgment logic formula of the second judgment module is:

[0037]

[0038] Where, Δv2 is the output signal of the second difference module; V ref2 is a second reference voltage;

[0039] The formula for the amplitude conversion ratio of the second proportional module is:

[0040]

[0041] Where, Δv2″ is the output signal of the second proportional module; P o is the rated output power of the switched reluctance motor; the preset value formula of the second reference voltage is:

[0042] V ref2 ≈v DCmax

[0043] In the formula, v DCmax The maximum value of the DC bus voltage output by the active power compensation circuit.

[0044] Beneficial effect: Compared with the prior art, the power double-compensation switched reluctance motor drive system described in the present invention has the following significant advantages: 1. Based on the replacement of large-capacity electrolytic capacitors with small-capacity film capacitors in parallel in the switched reluctance motor drive system, the problem of large motor output power pulsation in the small-capacitance switched reluctance motor drive system is solved by setting up two power compensations; specifically, the primary compensation circuit and control module directly collect the voltage pulsation on the AC bus side, and through simple signal processing, use the pulsating signal of the AC bus voltage as a compensation signal to drive the active power compensation circuit to achieve power compensation, thereby stabilizing the input voltage of the motor inverter. The control method is simple and reliable, and the problem of limited motor performance due to large fluctuations in the bus voltage is avoided; a voltage closed-loop control is adopted for the voltage across the capacitor in the compensation circuit, so that Within a reasonable voltage range, excessive voltage in the compensation circuit is avoided to damage the device, and it has high reliability; the secondary compensation circuit and control module directly collect the voltage signal of the DC bus pulsation, and through simple signal processing, dynamically adjust the PWM signal duty cycle of the switch tubes of each phase of the switched reluctance motor power main circuit with a compensation signal, and dynamically adjust the voltage of each phase winding, thereby simply and effectively realizing further compensation of the output torque; 2. For the same output power pulsation requirement, the use of double power compensation is more effective than the method of compensating only the winding voltage and does not cause waste of motor performance. Compared with the method of using only active power compensation circuit for compensation, the double power compensation method has lower requirements on the quota of components in the compensation circuit, which can correspondingly reduce the cost and size of the controller.

[0045] The control method of a power dual-compensation switched reluctance motor drive system described in the present invention better generates a switched reluctance motor drive signal and improves the reliability and life of the drive system by specifically setting the control quantities of each module in the primary compensation circuit and control module, and the secondary compensation circuit and control module. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Shown is a structural block diagram of the system of the present invention;

[0047] Figure 2 The DC bus voltage waveform of the switched reluctance motor drive system without electrolytic capacitor and power compensation is shown;

[0048] Figure 3 The figure shows the DC bus voltage waveform of the power double compensation type electrolytic capacitor-free switched reluctance motor drive system;

[0049] Figure 4 The output torque waveform of the power double compensation type electrolytic capacitor-free switched reluctance motor drive system with only primary power compensation and no secondary power compensation is shown;

[0050] Figure 5 The figure shows the output torque waveform of the power double compensation type electrolytic capacitor-free switched reluctance motor drive system of the present invention;

[0051] Figure 6 Shown is the corresponding waveform diagram of the asymmetric half-bridge power main circuit drive signal and the position signal. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0053] like Figure 1 As shown, a power double-compensation switched reluctance motor drive system provided by the present invention mainly includes two parts: a primary compensation circuit and a control part, and a secondary compensation circuit and a control part module.

[0054] 1. For the primary compensation circuit and control part:

[0055] The primary compensation circuit and control part specifically include an AC power supply, a rectifier bridge, an active power compensation circuit, a primary power compensation control module, and a first film capacitor;

[0056] The AC power supply is a single-phase sinusoidal AC power supply, both ends of which are connected to the AC input ends of the rectifier bridge, and the AC power supply is used to provide single-phase AC power to the rectifier bridge.

[0057] The rectifier bridge is a single-phase uncontrolled rectifier bridge, which is used to rectify the single-phase input alternating current into direct current and supply power to the active power compensation circuit.

[0058] The active power compensation circuit is a bidirectional DC-DC converter, which is used to absorb part of the power pulsation on the DC side of the rectifier bridge. Specifically, in this embodiment, the active power compensation circuit uses a boost bidirectional DC-DC converter, which specifically includes: an inductor L2, a first gate switch tube T1, a second gate switch tube T2, an inversion module, and a second film capacitor C2; the first gate switch tube and the second gate switch tube are both power switch tubes with anti-parallel diodes. One end of the inductor is connected to the positive output terminal of the rectifier bridge, and the other end of the inductor is respectively connected to the drain of the first gate switch tube and the source of the second gate tube; the source of the first gate switch tube is connected to the negative output terminal of the rectifier bridge; the gate of the first gate switch tube and the input end of the inversion module are both connected to the output end of the PWM signal generator; the output end of the inversion module is connected to the gate of the second gate switch tube, the drain of the second gate switch tube is connected to one end of the second film capacitor, and the other end of the second film capacitor is connected to the negative output terminal of the rectifier bridge. The active power compensation circuit may also be replaced by other DC-DC converters with dual switches that can achieve the same or similar power compensation effect, wherein the dual switches are controlled in a complementary conduction manner.

[0059] The primary power compensation control module specifically includes: an AC side voltage acquisition module, a first signal modulation module, a first summation module, a first voltage limiting module, a PWM signal generator, a first voltage acquisition module, a first reference voltage module, a first difference module, a first judgment module, a closed-loop regulator module, and a bias voltage module.

[0060] The AC side voltage acquisition module is used to collect the sinusoidal voltage signal of the AC power supply and transmit it to the first signal modulation module.

[0061] The first signal modulation module is used to modulate the sinusoidal voltage signal output by the AC side voltage acquisition module into a primary power compensation signal, and transmit it to the first summing module. Specifically, the first signal modulation module includes a multiplier module and a first proportional module; the multiplier module is used to perform a square operation on the AC voltage signal output by the AC side voltage acquisition module and transmit it to the first proportional module; the first proportional module is used to perform a proportional conversion on the amplitude of the multiplier output signal and transmit it to the first summing module, and the signal output by the first proportional module is the primary power compensation signal.

[0062] The first voltage acquisition module is used to acquire the voltage signal at both ends of the second film capacitor and transmit it to the first difference module.

[0063] The first reference voltage module is used to generate a first reference voltage and transmit the first reference voltage to the first difference module.

[0064] The first difference module is used to difference the voltage signal at both ends of the second film capacitor with the first reference voltage, and transmit the error signal obtained by the difference to the closed-loop regulator module.

[0065] The first judgment module is used to judge the output signal of the first difference module and select and transmit it to the closed-loop regulator module.

[0066] The closed-loop regulator module is used to adjust and correct the error signal output by the difference module and transmit it to the first summing module. The closed-loop regulator module uses a PI module; the PI module performs PI regulation on the output signal of the first judgment module and transmits it to the first summing module; the PI module can also be replaced by other types of regulators for closed-loop regulation.

[0067] The bias voltage module is used to generate a bias voltage and output it to the first summing module;

[0068] The first summing module is used to sum the primary power compensation signal with the error signal output by the closed-loop regulator module and the signal output by the bias voltage module and transmit the summing result to the first voltage limiting module;

[0069] The first voltage limiting module is used to limit the amplitude of the output signal of the first summing module and transmit it to the PWM signal generator; specifically, the output signal value of the first summing module is limited within the input range allowed by the PWM signal generator.

[0070] The PWM signal generator is used to convert the output signal of the first voltage limiting module into a PWM signal with a corresponding duty cycle. Specifically, the output signal of the first voltage limiting module is compared with a sawtooth carrier to generate a PWM signal.

[0071] The first film capacitor is connected in parallel between the active power compensation circuit and the switched reluctance motor power main circuit, and is used to stabilize the voltage at the input end of the switched reluctance motor power main circuit.

[0072] 2. For the secondary compensation circuit and control module:

[0073] The secondary compensation circuit and control part module specifically include a switched reluctance motor power main circuit, a switched reluctance motor, a position detection module, and a secondary power compensation control module.

[0074] The position detection module is used to detect the rotor position of the switched reluctance motor and send the rotor position signal to the secondary power compensation control module; the switched reluctance motor is an N-phase switched reluctance motor.

[0075] The second power compensation control module is used to generate a secondary power compensation signal according to the error value between the DC bus voltage (i.e., the voltage across capacitor C1) output by the active power compensation circuit and the reference voltage collected in real time, and to form a switch drive signal in combination with the rotor position signal and the secondary power compensation signal and transmit it to the switched reluctance motor power main circuit. Specifically, the secondary power compensation control module specifically includes a microcontroller, a second limiting module, a second signal modulation module, a second difference module, a second voltage acquisition module, and a second reference voltage module.

[0076] The second voltage acquisition module is used to acquire the DC bus voltage output by the active power compensation circuit in real time and transmit it to the second difference module;

[0077] The second reference voltage module is used to generate a second reference voltage and transmit the second reference voltage to the second difference module.

[0078] The second difference module is used to perform difference between the output signal of the second voltage acquisition module and the output signal of the second reference voltage module and transmit the difference to the second signal modulation module;

[0079] The second signal modulation module is used to modulate the output signal of the second summing module into a secondary power compensation signal and transmit it to the second limiting module; the second signal modulation module specifically includes a second judgment module and a second proportional module; the second judgment module is used to judge the output signal of the second difference module and select it for transmission to the second proportional module; the second proportional module is used to proportionally transform the amplitude of the output signal of the second judgment module and transmit it to the second limiting module, that is, the second proportional module is a secondary power compensation signal.

[0080] The second amplitude limiting module is used to limit the amplitude of the output signal of the second signal modulation module and transmit it to the microcontroller;

[0081] The microcontroller is used to form a switch tube driving control signal in the power main circuit of the switched reluctance motor according to the rotor position signal and the signal output by the second limiting module.

[0082] The switched reluctance motor power main circuit is used to receive a switch tube drive control signal and drive the switched reluctance motor according to the switch tube drive control signal. The switched reluctance motor power main circuit uses an asymmetric half-bridge power main circuit, specifically an N-phase asymmetric half-bridge circuit, where N is an integer greater than or equal to 2. The asymmetric half-bridge power main circuit can also be replaced by other power main circuits for driving a switched reluctance motor.

[0083] Working principle of this system:

[0084] The primary compensation circuit and control part generate a PWM signal. The PWM signal drives the active power compensation circuit and absorbs part of the power pulsation on the DC side of the rectifier bridge. The specific principle is:

[0085] The AC side voltage acquisition module collects the single-phase AC side input voltage v in real time ac ; The input voltage is rectified and multiplied by the multiplier to obtain v in Signal; v in The amplitude of the signal is transformed by a certain ratio to obtain a power compensation signal x in ; The first voltage acquisition module collects the voltage v across the capacitor C2 in real time C2 , the voltage signal v collected across the capacitor C2 C2 With reference voltage V ref1 The error signal Δv1 of the voltage across the capacitor C2 is obtained by difference. The error signal is selected by judgment to obtain the Δv1′ signal, and then the capacitor C2 voltage feedback signal x1 is obtained after PI adjustment. The primary power compensation signal x in , capacitor C2 voltage feedback signal x1 and bias voltage signal v BB The PWM reference signal x is obtained by superposition, summation and limiting. rate , x rateThe signal is compared with the sawtooth carrier to generate a PWM signal with a corresponding duty cycle, which is used to drive the switch tube of the active power compensation circuit. The PWM signal generated by the PWM signal generator is divided into two paths, one is sent to the driving end of the switch tube T1 in the active power compensation circuit, and the other is sent to the inversion module to invert the high and low levels of the PWM signal and send it to the driving end of the switch tube T2 in the active power compensation circuit.

[0086] When the power of the DC bus pulsates, the PWM signals of the two switching tubes T1 and T2 are adjusted. BB 、ns BB The duty cycle change of the bidirectional converter can control the energy flow direction of the bidirectional converter, thereby absorbing the DC bus power pulsation; when the power of the DC bus is higher or lower than the average power of the DC bus, the primary side power compensation signal x rate Under the dynamic regulation of the PWM signal s of the two switch tubes T1 and T2 BB 、ns BB The duty cycle of the bidirectional converter changes accordingly, thereby controlling the energy of the bidirectional converter to flow from the DC bus side to the capacitor C2 or the capacitor C2 to release the energy to the DC bus.

[0087] The secondary compensation circuit and control part module generate the switch tube drive control signal. The specific principle of the N-phase asymmetric half-bridge circuit dynamically driving the winding voltage of each phase of the N-phase switched reluctance motor according to the drive control signal is as follows:

[0088] The second voltage acquisition module collects the voltage v across the first film capacitor C1 in real time DC , the collected DC bus voltage v DC With reference voltage V ref2 The DC bus voltage error signal Δv2 is obtained by difference; the error signal is judged and gated to obtain the Δv2′ signal, and the amplitude of the gated signal is converted by a certain ratio to obtain the secondary power compensation signal Δv2″. The secondary power compensation signal Δv2″ is limited to obtain the x2 signal and sent to the microcontroller. The microcontroller is based on the position signal p x The change of x2 turns on and off the switch tube of the asymmetric half-bridge power main circuit, thereby driving the corresponding phase of the switched reluctance motor; according to the change of x2 signal, the PWM signal s of the upper tube of the asymmetric half-bridge power main circuit is dynamically adjusted. AH 、s BH The duty cycle of each phase winding can be dynamically adjusted.

[0089] Asymmetric half-bridge power main circuit drive signal s XL 、s XH With position signal p X The corresponding waveform is as follows Figure 6 As shown, where X is A, B, C.... Where s XLThe square wave driving signal sent by the microcontroller to the lower tube of the X-phase bridge arm of the asymmetric half-bridge power main circuit, s XH It is the PWM signal sent by the microcontroller to the upper tube of the X-phase bridge arm of the asymmetric half-bridge power main circuit, and its PWM duty cycle is d sXH ′, its calculation expression is as follows:

[0090] d sXH ′=d sXH +kx2

[0091] Where, d sXH is the duty cycle of the PWM signal of the X-phase upper tube of the asymmetric half-bridge power main circuit when the x2 signal value is 0, kx2 is the compensation amount of the PWM signal duty cycle, and k is the conversion coefficient of the x2 signal into the PWM signal duty cycle compensation amount.

[0092] like Figure 2 As shown, in the prior art, when there is no power compensation and the DC bus is only connected in parallel with a small-capacity capacitor, the DC bus voltage fluctuates periodically at twice the frequency of the AC side input voltage, and the fluctuation amplitude is large. Figure 3 As shown in the figure, if the pulsating signal of the AC bus voltage is captured in real time and modulated into a compensation signal to control the active power compensation circuit, and then realize the primary power compensation, the effect of this part of the power compensation is to significantly reduce the fluctuation of the DC bus voltage. However, when there is only the primary power compensation part and no secondary power compensation, the DC bus voltage still has a certain fluctuation. In this case, if Figure 4 As shown in FIG. 1 , the fluctuation of the DC bus voltage will further cause the fluctuation of the motor output torque. The secondary power compensation method of the present invention detects the DC bus voltage in real time and compares it with the reference voltage. The error signal obtained is modulated as the secondary power compensation signal to dynamically adjust the duty cycle of the power main circuit PWM signal, thereby realizing dynamic compensation of the winding voltage. Figure 5 As shown, the motor output torque is finally stabilized. Figure 4 and Figure 5 It can be seen that, compared with the prior art, the output torque of the motor output by the method described in the present application is more stable.

[0093] In addition, the present invention also provides a control method for a power double-compensation switched reluctance motor drive system, comprising the following steps:

[0094] (1) Setting the amplitude conversion ratio of the first proportional module in the primary power compensation control module, setting the preset value of the bias voltage, setting the judgment logic of the first judgment module, and setting the preset value of the first reference voltage; according to the voltage v collected in real time by the AC side voltage collection module ac , the voltage v across the second film capacitor collected in real time by the first voltage collection moduleC2 Get the final generated PWM signal;

[0095] The amplitude conversion ratio conversion formula of the first proportional module is specifically:

[0096]

[0097] In the formula, v in is the multiplier output signal; x in is the primary power compensation signal output by the first proportional module; v c2max is the upper limit of the voltage of the second film capacitor, v c2min is the lower limit of the voltage of the second film capacitor; V DC is the average voltage of the DC bus, v acmax is the maximum value of AC bus voltage;

[0098] The specific formula for the preset value of the bias voltage is:

[0099]

[0100] In the formula, v BB is the bias voltage signal; D min The active power compensation circuit driving signal s BB The minimum duty cycle value of

[0101] The specific formula of the judgment logic of the first judgment module is:

[0102]

[0103] Wherein, Δv1 is the output signal of the first difference module; Δv1' is the output signal of the first judgment module; V ref1 is a first reference voltage;

[0104] The first reference voltage V ref1 The specific formula for the preset value is:

[0105] V ref1 =(0.3~0.5)V CN

[0106] Where V CN is the nominal rated voltage value of capacitor C2;

[0107] (2) setting the amplitude conversion ratio of the second proportional module in the secondary power compensation control module, setting the judgment logic of the second judgment module, and setting the preset value of the second reference voltage; according to the DC bus voltage v output by the active power compensation circuit collected in real time by the second voltage collection module DC Obtain the switch tube drive control signal output by the microprocessor;

[0108] The judgment logic formula of the second judgment module is:

[0109]

[0110] Where, Δv2 is the output signal of the second difference module; V ref2 is a second reference voltage;

[0111] The formula for the amplitude conversion ratio of the second proportional module is:

[0112]

[0113] Where, Δv2″ is the output signal of the second proportional module; P o is the rated output power of the switched reluctance motor;

[0114] The preset value formula of the second reference voltage is:

[0115] V ref2 ≈v DCmax

[0116] In the formula, v DCmax The maximum value of the DC bus voltage output by the active power compensation circuit.

Claims

1. A power double-compensation switched reluctance motor drive system, characterized in that: include: Primary compensation circuit and control part, secondary compensation circuit and control part; The primary compensation circuit and control part include: an AC power supply, a rectifier bridge, a first film capacitor, an active power compensation circuit, and a primary power compensation control module; the secondary compensation circuit and control part include a switched reluctance motor power main circuit, a switched reluctance motor, a position detection module, and a secondary power compensation control module; The AC power supply is a single-phase sinusoidal AC power supply, and both ends of the AC power supply are connected to the AC input ends of the rectifier bridge to provide single-phase sinusoidal AC power to the rectifier bridge; the rectifier bridge is used to rectify the input single-phase sinusoidal AC power into DC power and supply power to the active power compensation circuit; the active power compensation circuit connected in parallel with the rectifier bridge is a bidirectional DC-DC converter, which is used to absorb the power pulsation at the DC output end of the rectifier bridge; the primary power compensation control module is used to generate a primary power compensation signal according to the AC bus voltage output by the AC power supply collected in real time and convert it into a PWM signal with a corresponding duty cycle to drive the active power compensation circuit; The first film capacitor is connected in parallel between the active power compensation circuit and the switched reluctance motor power main circuit, and is used to stabilize the voltage at the input end of the switched reluctance motor power main circuit; The position detection module is used to detect the rotor position of the switched reluctance motor and send the rotor position signal to the secondary power compensation control module; the secondary power compensation control module is used to generate a secondary power compensation signal according to the error value between the DC bus voltage output by the active power compensation circuit and the reference voltage collected in real time, and combine the rotor position signal and the secondary power compensation signal to form a switch drive control signal and transmit it to the switched reluctance motor power main circuit; the switched reluctance motor power main circuit is used to receive the switch tube drive control signal and control the switched reluctance motor according to the switch tube drive control signal; The bidirectional DC-DC converter has a second film capacitor for absorbing or releasing converter energy; the primary power compensation control module specifically includes: an AC side voltage acquisition module, a first signal modulation module, a first summing module, a first voltage limiting module, a PWM signal generator, a first voltage acquisition module, a first reference voltage module, a first difference module, and a closed-loop regulator module; The AC side voltage acquisition module is used to acquire the sinusoidal voltage signal of the AC power supply and transmit it to the first signal modulation module; the first signal modulation module is used to modulate the sinusoidal voltage signal output by the AC side voltage acquisition module into a primary power compensation signal, and transmit it to the first summing module; the first voltage acquisition module is used to acquire the voltage signal at both ends of the second film capacitor and transmit it to the first difference module; the first reference voltage module is used to generate a first reference voltage and transmit it to the first difference module; the first difference module is used to differ the voltage signal at both ends of the second film capacitor from the first reference voltage, and transmit the error signal obtained by the difference to the closed-loop regulator module; the closed-loop regulator module is used to adjust and correct the error signal output by the difference module and transmit it to the first summing module; the first summing module is used to sum the signal transmitted to the first summing module and transmit the summing result to the first voltage limiting module; the first voltage limiting module is used to limit the amplitude of the output signal of the first summing module and transmit it to the PWM signal generator; the PWM signal generator is used to convert the output signal of the first voltage limiting module into a PWM signal with a corresponding duty cycle; The first signal modulation module includes a multiplier module and a first proportional module; the multiplier module is used to perform a square operation on the AC voltage signal output by the AC side voltage acquisition module and transmit it to the first proportional module; the first proportional module is used to perform a proportional transformation on the amplitude of the multiplier output signal and transmit it to the first summation module.

2. The power double-compensated switched reluctance motor drive system according to claim 1, characterized in that: The secondary power compensation control module specifically includes a microcontroller, a second limiting module, a second signal modulation module, a second difference module, a second voltage acquisition module, and a second reference voltage module; The second voltage acquisition module is used to acquire the DC bus voltage output by the active power compensation circuit in real time and transmit it to the second difference module; The second reference voltage module is used to generate a second reference voltage and transmit it to the second difference module; The second difference module is used to perform difference between the output signal of the second voltage acquisition module and the output signal of the second reference voltage module and transmit the difference to the second signal modulation module; The second signal modulation module is used to modulate the output signal of the second summing module into a secondary power compensation signal and transmit it to the second limiting module; the second limiting module is used to limit the amplitude of the output signal of the second signal modulation module and transmit it to the microcontroller; the microcontroller is used to form a switch tube drive control signal in the power main circuit of the switched reluctance motor according to the rotor position signal and the signal output by the second limiting module.

3. The power double-compensated switched reluctance motor drive system according to claim 1, characterized in that: The bidirectional DC-DC converter is a boost type DC-DC bidirectional converter, which specifically includes an inductor, a first gate switch tube, a second gate switch tube, an inversion module, and a second film capacitor; One end of the inductor is connected to the positive rectifier output terminal of the rectifier bridge, and the other end of the inductor is respectively connected to the drain of the first selection switch tube and the source of the second selection switch tube; the source of the first selection switch tube is connected to the negative rectifier output terminal of the rectifier bridge; the gate of the first selection switch tube and the input end of the inversion module are both connected to the output end of the PWM signal generator; the output end of the inversion module is connected to the gate of the second selection switch tube, the drain of the second selection switch tube is connected to one end of the second film capacitor, and the other end of the second film capacitor is connected to the negative rectifier output terminal of the rectifier bridge; the first selection switch tube and the second selection switch tube are both power switch tubes with anti-parallel diodes.

4. The power double-compensated switched reluctance motor drive system according to claim 3, characterized in that: The primary power compensation control module also includes a bias voltage module and a first judgment module; the first judgment module is used to judge the output signal of the first difference module and select and transmit it to the closed-loop regulator module; the bias voltage module is used to generate a bias voltage and output it to the first summation module.

5. The power double-compensated switched reluctance motor drive system according to claim 4, characterized in that: The closed-loop regulator module is a PI module or a module used to perform closed-loop regulation on the error signal output by the first difference module; when the closed-loop regulator module selects the PI module, the PI module performs PI regulation on the output signal of the first judgment module and transmits it to the first summation module.

6. The power double-compensated switched reluctance motor drive system according to claim 2, characterized in that: The switched reluctance motor power main circuit is an N-phase asymmetric half-bridge circuit, where N is a positive integer greater than 2.

7. According to the power dual-compensation switched reluctance motor drive system described in claim 2, the second signal modulation module specifically includes a second judgment module and a second proportional module; the second judgment module is used to judge the output signal of the second difference module and select it for transmission to the second proportional module; the second proportional module is used to proportionally transform the amplitude of the output signal of the second judgment module and transmit it to the second limiting module.

8. A control method for the power double-compensated switched reluctance motor drive system according to claim 5, characterized in that: The following steps are involved: (1) Setting the amplitude conversion ratio of the first proportional module in the primary power compensation control module, setting the preset value of the bias voltage, setting the judgment logic of the first judgment module, and setting the preset value of the first reference voltage; according to the voltage v collected in real time by the AC side voltage collection module ac , the voltage v across the second film capacitor collected in real time by the first voltage collection module C2 Get the final generated PWM signal; The amplitude conversion ratio conversion formula of the first proportional module is specifically: In the formula, v in is the multiplier output signal; x in is the primary power compensation signal output by the first proportional module; v c2max is the upper limit of the voltage of the second film capacitor, v c2min is the lower limit of the voltage of the second film capacitor; V DC is the average voltage of the DC bus, v acmax is the maximum value of AC bus voltage; The specific formula for the preset value of the bias voltage is: In the formula, v BB is the bias voltage signal; D min The active power compensation circuit driving signal s BB The minimum duty cycle value of The specific formula of the judgment logic of the first judgment module is: Wherein, Δv1 is the output signal of the first difference module; Δv1' is the output signal of the first judgment module; V ref1 is a first reference voltage; The first reference voltage V ref1 The specific formula for the preset value is: V ref1 =(0.3~0.5)V CN Where V CN is the nominal rated voltage value of capacitor C2; (2) setting the amplitude conversion ratio of the second proportional module in the secondary power compensation control module, setting the judgment logic of the second judgment module, and setting the preset value of the second reference voltage; according to the DC bus voltage v output by the active power compensation circuit collected in real time by the second voltage collection module DC Obtain the switch tube drive control signal output by the microprocessor; The judgment logic formula of the second judgment module is: Where, Δv2 is the output signal of the second difference module; V ref2 is a second reference voltage; The formula for the amplitude conversion ratio of the second proportional module is: Where, Δv2″ is the output signal of the second proportional module; P o is the rated output power of the switched reluctance motor; The preset value formula of the second reference voltage is: In ref2 ≈in DCmax In the formula, v DCmax The maximum value of the DC bus voltage output by the active power compensation circuit.

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