A Method for Controlling the Output Voltage of a Ring-Winding Structure SRG System

Abstract

The present invention relates to the field of power generation technology, and specifically to a method for controlling the output voltage of a ring-winding structure SRG system. This method is implemented through the following steps: Step 1: Improve the existing ring-winding structure SRG system. The improved ring-winding structure SRG system includes a DC voltage source, a DC-DC half-bridge circuit, a ring-winding structure SRG, a full-bridge power converter, a load resistor, and an output capacitor; Step 2: During the operation of the system, perform the following controls on the system: a) Collect the actual rotational speed of the ring-winding structure SRG; b) Collect the three-phase actual phase currents and three-phase actual line currents of the ring-winding structure SRG; c) Collect the actual output voltage of the system. The present invention solves the problem that the output voltage of the existing ring-winding structure SRG system is uncontrollable and fluctuates greatly, and is applicable to the ring-winding structure SRG system.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation, and specifically to a method for controlling the output voltage of a ring-winding structure SRG system. Background Art

[0002] SRG (Switched Reluctance Generator) systems are developed and applied in fields such as aircraft, hybrid vehicles, electric vehicles, and wind power generation due to their advantages of simple and robust structure and low cost. Among various SRG systems, the ring-winding structure SRG system has the advantage of low copper loss because it integrates AC and DC. As Figure 1 shown, under the existing technical conditions, the ring-winding structure SRG system includes a DC voltage source V1, a ring-winding structure SRG, a three-phase uncontrolled rectifier circuit, and a load resistor R1. In this system, the DC voltage source V1 directly provides circulating current and excitation energy to the ring-winding structure SRG, and the ring-winding structure SRG outputs DC voltage through the three-phase uncontrolled rectifier circuit. However, in practical applications, due to its own structural limitations, this system has the problems of uncontrollable output voltage and extremely large fluctuations, resulting in limited application scope. Based on this, the present invention proposes a method for controlling the output voltage of a ring-winding structure SRG system, which first applies a full-bridge power converter to the ring-winding structure SRG system to solve the problems of uncontrollable output voltage and extremely large fluctuations in the existing ring-winding structure SRG system. Summary of the Invention

[0003] The present invention provides a method for controlling the output voltage of a ring-winding structure SRG system to solve the problems of uncontrollable output voltage and extremely large fluctuations in the existing ring-winding structure SRG system.

[0004] The present invention is implemented by the following technical solutions:

[0005] A method for controlling the output voltage of a ring-winding structure SRG system, which is implemented by the following steps:

[0006] Step 1: Improve the existing ring-winding structure SRG system. The improved ring-winding structure SRG system includes a DC voltage source, a DC-DC half-bridge circuit, a ring-winding structure SRG, a full-bridge power converter, a load resistor, and an output capacitor;

[0007] Two output terminals of the DC voltage source are respectively connected to two input terminals of the DC-DC half-bridge circuit; two output terminals of the DC-DC half-bridge circuit are respectively connected to both ends of the ring winding of the ring-winding structure SRG; three output terminals of the ring-winding structure SRG are respectively connected to three AC terminals of the full-bridge power converter; the load resistor and the output capacitor are both connected in parallel to two DC terminals of the full-bridge power converter;

[0008] Step 2: During the operation of the system, the following controls are performed on the system:

[0009] a) Collect the actual rotational speed of the SRG with a toroidal winding structure, subtract the actual rotational speed from the set reference rotational speed to obtain a rotational speed difference, send the rotational speed difference into a rotational speed PI controller, and the rotational speed PI controller outputs the input torque of the SRG with a toroidal winding structure according to the rotational speed difference;

[0010] b) Collect the three-phase actual phase currents and three-phase actual line currents of the SRG with a toroidal winding structure, and calculate the actual circulating current of the SRG with a toroidal winding structure according to the collection results; the specific calculation formula is as follows:

[0011]

[0012] Where: I cc represents the actual circulating current; i pc represents the actual phase current of phase C; i la represents the actual line current of phase A; i lb represents the actual line current of phase B;

[0013] Subtract the actual circulating current from the set reference circulating current to obtain a circulating current difference, send the circulating current difference into a circulating current PID controller, and the circulating current PID controller outputs a modulation signal according to the circulating current difference;

[0014] Perform PWM modulation on the modulation signal and a triangular wave to obtain a switching control signal, and apply the switching control signal to two IGBTs of a DC-DC half-bridge circuit, so that the DC-DC half-bridge circuit outputs an equivalent voltage source, thereby providing a circulating current and partial excitation energy to the SRG with a toroidal winding structure;

[0015] c) Collect the actual output voltage of the system, subtract the actual output voltage from the set reference output voltage to obtain an output voltage difference, send the output voltage difference into an output voltage PI controller, and the output voltage PI controller outputs the peak value of the reference line current according to the output voltage difference;

[0016] Collect the three-phase Hall signals of the SRG with a toroidal winding structure, send the three-phase Hall signals into a decoder controlled by a six-step commutation method, and the decoder outputs three-phase back electromotive forces according to the three-phase Hall signals;

[0017] The three-phase back electromotive force is multiplied by the peak value of the reference line current to obtain the three-phase reference line current. The difference between the three-phase reference line current and the three-phase actual line current is calculated to obtain the three-phase line current difference. The three-phase line current difference is fed into a hysteresis controller, and the hysteresis controller outputs a switching control signal according to the three-phase line current difference. The switching control signal is applied to the six IGBTs of the full-bridge power converter to achieve current chopping control;

[0018] When the switching control signal is at a low level, the full-bridge power converter operates in the rectification mode. The toroidal winding structure SRG outputs a DC voltage through the six diodes of the full-bridge power converter and charges the output capacitor;

[0019] When the switching control signal is at a high level, the full-bridge power converter operates in the inversion mode. The output capacitor discharges and provides part of the exciting energy to the toroidal winding structure SRG through the six IGBTs of the full-bridge power converter, thereby making the actual output voltage consistent with the reference output voltage.

[0020] The DC-DC half-bridge circuit and the full-bridge power converter are both well-known existing structures.

[0021] Compared with the existing toroidal winding structure SRG system, the output voltage control method of the toroidal winding structure SRG system of the present invention improves the existing toroidal winding structure SRG system, and designs a series of feedback loops (speed feedback loop, circulating current feedback loop, line current feedback loop, output voltage feedback loop) for the improved toroidal winding structure SRG system. As a result, the output voltage of the system is controllable and the fluctuation is extremely small, so that the applicable range of the system is no longer limited.

[0022] In order to verify the beneficial effects of the present invention, simulation experiments are carried out on the existing toroidal winding structure SRG system and the improved toroidal winding structure SRG system, and the output voltage waveform diagrams and the comparison tables of the output voltage and effective value of the two are obtained, which are as follows:

[0023] I. When the reference speed is set to 500 r / min, the reference circulating current is set to 2 A, and the load resistance is set to 50 Ω, the output voltage waveform diagrams of the two are as Figure 4 shown.

[0024] II. When the reference speed is set to 500 r / min, the reference circulating current is set to 2 A, and the load resistance is set to 100 Ω, the output voltage waveform diagrams of the two are as Figure 5 shown.

[0025] III. When the reference speed is set to 500 r / min, the reference circulating current is set to 3 A, and the load resistance is set to 50 Ω, the output voltage waveform diagrams of the two are as Figure 6 shown.

[0026] IV. When the reference rotational speed is set to 500 r / min, the reference circulating current is set to 3 A, and the load resistance is set to 100 Ω, the output voltage waveforms of the two are as shown in Figure 7 the figure.

[0027] V. When the reference rotational speed is set to 1000 r / min, the reference circulating current is set to 2 A, and the load resistance is set to 50 Ω, the output voltage waveforms of the two are as shown in Figure 8 the figure.

[0028] VI. When the reference rotational speed is set to 1000 r / min, the reference circulating current is set to 2 A, and the load resistance is set to 100 Ω, the output voltage waveforms of the two are as shown in Figure 9 the figure.

[0029] VII. When the reference rotational speed is set to 1000 r / min, the reference circulating current is set to 3 A, and the load resistance is set to 50 Ω, the output voltage waveforms of the two are as shown in Figure 10 the figure.

[0030] VIII. When the reference rotational speed is set to 1000 r / min, the reference circulating current is set to 3 A, and the load resistance is set to 100 Ω, the output voltage waveforms of the two are as shown in Figure 11 the figure.

[0031] IX. When the load resistance is set to 50 Ω, the comparison table of the output voltage and the effective value of the two is as follows:

[0032]

[0033] X. When the load resistance is set to 100 Ω, the comparison table of the output voltage and the effective value of the two is as follows:

[0034]

[0035] It can be seen from the output voltage waveforms of the two and the comparison table of the output voltage and the effective value that: the output voltage of the existing SRG system with a toroidal winding structure is uncontrollable and fluctuates greatly. The output voltage of the improved SRG system with a toroidal winding structure is controllable and fluctuates very little, and the control effect is good.

[0036] The present invention effectively solves the problem that the output voltage of the existing SRG system with a toroidal winding structure is uncontrollable and fluctuates greatly, and is applicable to the SRG system with a toroidal winding structure. Description of the Drawings

[0037] Figure 1 is the schematic diagram of the existing SRG system with a toroidal winding structure.

[0038] Figure 2 is the schematic diagram of the improved SRG system with a toroidal winding structure.

[0039] Figure 3 is the control block diagram of the present invention.

[0040] Figure 4 are the output voltage waveforms of the existing ring winding structure SRG system and the improved ring winding structure SRG system Figure 1 .

[0041] Figure 5 are the output voltage waveforms of the existing ring winding structure SRG system and the improved ring winding structure SRG system Figure 2 .

[0042] Figure 6 are the output voltage waveforms of the existing ring winding structure SRG system and the improved ring winding structure SRG system Figure 3 .

[0043] Figure 7 are the output voltage waveforms of the existing ring winding structure SRG system and the improved ring winding structure SRG system Figure 4 .

[0044] Figure 8 are the output voltage waveforms of the existing ring winding structure SRG system and the improved ring winding structure SRG system Figure 5 .

[0045] Figure 9 are the output voltage waveforms of the existing ring winding structure SRG system and the improved ring winding structure SRG system Figure 6 .

[0046] Figure 10 are the output voltage waveforms of the existing ring winding structure SRG system and the improved ring winding structure SRG system Figure 7 .

[0047] Figure 11 are the output voltage waveforms of the existing ring winding structure SRG system and the improved ring winding structure SRG system Figure 8 .

[0048] In the figure: V1 represents the DC voltage source of the existing SRG system with a toroidal winding structure; D1 represents the first diode of the three-phase uncontrolled rectifier circuit; D2 represents the second diode of the three-phase uncontrolled rectifier circuit; D3 represents the third diode of the three-phase uncontrolled rectifier circuit; D4 represents the fourth diode of the three-phase uncontrolled rectifier circuit; D5 represents the fifth diode of the three-phase uncontrolled rectifier circuit; D6 represents the sixth diode of the three-phase uncontrolled rectifier circuit; R1 represents the load resistor of the existing SRG system with a toroidal winding structure; V2 represents the DC voltage source of the improved SRG system with a toroidal winding structure; C1 represents the first capacitor of the DC-DC half-bridge circuit; C2 represents the second capacitor of the DC-DC half-bridge circuit; Q1 represents the first IGBT of the DC-DC half-bridge circuit; Q2 represents the second IGBT of the DC-DC half-bridge circuit; D7 represents the first diode of the DC-DC half-bridge circuit; D8 represents the second diode of the DC-DC half-bridge circuit; T represents the transformer of the DC-DC half-bridge circuit; D9 represents the third diode of the DC-DC half-bridge circuit; D10 represents the fourth diode of the DC-DC half-bridge circuit; I cc represents the actual circulating current; i la represents the actual line current of phase A; i lb represents the actual line current of phase B; i lc represents the actual line current of phase C; Q3 represents the first IGBT of the full-bridge power converter; Q4 represents the second IGBT of the full-bridge power converter; D11 represents the first diode of the full-bridge power converter; D12 represents the second diode of the full-bridge power converter; Q5 represents the third IGBT of the full-bridge power converter; Q6 represents the fourth IGBT of the full-bridge power converter; D13 represents the third diode of the full-bridge power converter; D14 represents the fourth diode of the full-bridge power converter; Q7 represents the fifth IGBT of the full-bridge power converter; Q8 represents the sixth IGBT of the full-bridge power converter; D15 represents the fifth diode of the full-bridge power converter; D16 represents the sixth diode of the full-bridge power converter; R2 represents the load resistor of the improved SRG system with a toroidal winding structure; C3 represents the output capacitor. Specific implementation mode

[0049] A method for controlling the output voltage of an SRG system with a toroidal winding structure, which is implemented by the following steps:

[0050] Step 1: Improve the existing SRG system with a toroidal winding structure. The improved SRG system with a toroidal winding structure includes a DC voltage source V2, a DC-DC half-bridge circuit, a toroidal winding structure SRG, a full-bridge power converter, a load resistor R2, and an output capacitor C3;

[0051] The two output terminals of the DC voltage source V2 are respectively connected to the two input terminals of the DC-DC half-bridge circuit; the two output terminals of the DC-DC half-bridge circuit are respectively connected to the two ends of the toroidal winding of the toroidal winding structure SRG; the three output terminals of the toroidal winding structure SRG are respectively connected to the three AC terminals of the full-bridge power converter; the load resistor R2 and the output capacitor C3 are both connected in parallel to the two DC terminals of the full-bridge power converter;

[0052] Step 2: During the operation of the system, the following controls are performed on the system:

[0053] a) Collect the actual rotational speed of the toroidal winding structure SRG, subtract the actual rotational speed from the set reference rotational speed to obtain a rotational speed difference, send the rotational speed difference to the rotational speed PI controller, and the rotational speed PI controller outputs the input torque of the toroidal winding structure SRG according to the rotational speed difference;

[0054] b) Collect the three-phase actual phase currents and three-phase actual line currents of the toroidal winding structure SRG, and calculate the actual circulating current of the toroidal winding structure SRG according to the collected results; the specific calculation formula is as follows:

[0055]

[0056] where: I cc represents the actual circulating current; i pc represents the actual phase current of phase C; i la represents the actual line current of phase A; i lb represents the actual line current of phase B;

[0057] Subtract the actual circulating current from the set reference circulating current to obtain a circulating current difference, send the circulating current difference to the circulating current PID controller, and the circulating current PID controller outputs a modulation signal according to the circulating current difference;

[0058] Perform PWM modulation on the modulation signal and the triangular wave to obtain a switching control signal, and apply the switching control signal to the two IGBTs of the DC-DC half-bridge circuit, so that the DC-DC half-bridge circuit outputs an equivalent voltage source, thereby providing a circulating current and partial excitation energy to the toroidal winding structure SRG;

[0059] c) Collect the actual output voltage of the system, subtract the actual output voltage from the set reference output voltage to obtain an output voltage difference, send the output voltage difference to the output voltage PI controller, and the output voltage PI controller outputs the peak value of the reference line current according to the output voltage difference;

[0060] Collect the three-phase Hall signals of the toroidal winding structure SRG, send the three-phase Hall signals to the decoder controlled by the six-step commutation method, and the decoder outputs the three-phase back electromotive force according to the three-phase Hall signals;

[0061] The three-phase reference line currents are obtained by multiplying the three-phase back electromotive forces by the peak values of the reference line currents. The three-phase line current differences are obtained by subtracting the three-phase actual line currents from the three-phase reference line currents. The three-phase line current differences are fed into a hysteresis controller, and the hysteresis controller outputs a switching control signal according to the three-phase line current differences. The switching control signal is applied to the six IGBTs of the full-bridge power converter to achieve current chopping control;

[0062] When the switching control signal is at a low level, the full-bridge power converter operates in a rectification mode. The toroidal winding structure SRG outputs a DC voltage through the six diodes of the full-bridge power converter and charges the output capacitor C3;

[0063] When the switching control signal is at a high level, the full-bridge power converter operates in an inversion mode. The output capacitor C3 discharges and provides part of the exciting energy to the toroidal winding structure SRG through the six IGBTs of the full-bridge power converter, thereby making the actual output voltage consistent with the reference output voltage.

[0064] In specific implementation, in the second step, the frequency of the triangular wave is 5000 Hz.

[0065] Although the specific implementation manners of the present invention have been described above, those skilled in the art should understand that these are only examples. The protection scope of the present invention is defined by the appended claims. Without departing from the principle and essence of the present invention, those skilled in the art can make various changes or modifications to these implementation modes, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for controlling output voltage of a toroidal winding structure SRG system, characterized in that: This method is implemented by the following steps: Step 1: improving the existing toroidal winding structure SRG system, the improved toroidal winding structure SRG system includes a DC voltage source (V2), a DC-DC half-bridge circuit, a toroidal winding structure SRG, a full-bridge power converter, a load resistor (R2), and an output capacitor (C3); The two output ends of the DC voltage source (V2) are respectively connected to the two input ends of the DC-DC half-bridge circuit; the two output ends of the DC-DC half-bridge circuit are respectively connected to the two ends of the ring winding of the ring winding structure SRG; the three output ends of the ring winding structure SRG are respectively connected to the three AC ends of the full-bridge power converter; the load resistor (R2) and the output capacitor (C3) are both connected in parallel to the two DC ends of the full-bridge power converter; Step 2: During system operation, the system is controlled as follows: a) collecting the actual speed of the ring winding structure SRG, subtracting the actual speed from the set reference speed to obtain a speed difference, sending the speed difference to a speed PI controller, and the speed PI controller outputs the input torque of the ring winding structure SRG according to the speed difference; b) Collect the three-phase actual phase current and the three-phase actual line current of the ring winding structure SRG, and calculate the actual circulating current of the ring winding structure SRG according to the collected results; the specific calculation formula is as follows: Where: I cc Indicates the actual circulating current; i pc Indicates the actual phase current of phase C; i la Indicates the actual line current of phase A; i lb Indicates the actual line current of phase B; The actual circulating current is subtracted from the set reference circulating current to obtain a circulating current difference, and the circulating current difference is sent to a circulating current PID controller, and the circulating current PID controller outputs a modulation signal according to the circulating current difference; A switching control signal is obtained by PWM modulating the modulation signal and the triangular wave, and the switching control signal is applied to two IGBTs of the DC-DC half-bridge circuit, so that the DC-DC half-bridge circuit outputs an equivalent voltage source, thereby providing a circulating current and part of the excitation energy to the toroidal winding structure SRG; c) Acquire the actual output voltage of the system, subtract the actual output voltage from the set reference output voltage to obtain the output voltage difference, send the output voltage difference to the output voltage PI controller, and the output voltage PI controller outputs the peak value of the reference line current according to the output voltage difference; Collect the three-phase Hall signal of the ring winding structure SRG, send the three-phase Hall signal to the decoder controlled by the six-step commutation method, and the decoder outputs three-phase back electromotive force according to the three-phase Hall signal; The three-phase back electromotive force is multiplied by the peak value of the reference line current to obtain the three-phase reference line current, the three-phase reference line current is subtracted from the three-phase actual line current to obtain the three-phase line current difference, the three-phase line current difference is sent to the hysteresis controller, the hysteresis controller outputs a switch control signal according to the three-phase line current difference, and the switch control signal is applied to the six IGBTs of the full-bridge power converter to realize current chopping control; When the switch control signal is at a low level, the full-bridge power converter operates in a rectification mode, and the ring winding structure SRG outputs a DC voltage through six diodes of the full-bridge power converter and charges the output capacitor (C3); When the switch control signal is at a high level, the full-bridge power converter operates in the inverter mode, the output capacitor (C3) is discharged, and part of the excitation energy is provided to the ring winding structure SRG through the six IGBTs of the full-bridge power converter, thereby making the actual output voltage consistent with the reference output voltage.

2. The output voltage control method of a toroidal winding structure SRG system according to claim 1, characterized in that: In the step 2, the frequency of the triangle wave is 5000 Hz.

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