Switched reluctance motor high-precision speed control system for electric vehicle

Abstract

The utility model provides a switched reluctance motor high-precision speed control system for an electric automobile, and the system comprises a speed sensor which is electrically connected with a switched reluctance motor and is used for collecting the actual rotating speed signal of a rotor of the switched reluctance motor; the controller is electrically connected with the speed sensor; the driving control circuit is electrically connected with the controller and receives a driving control instruction sent by the controller according to the actual rotating speed signal, so that the driving control circuit generates a pulse signal according to the driving control instruction, and the rotating speed of the switched reluctance motor is controlled through the pulse signal; the drive control circuit comprises a pulse width modulation control circuit electrically connected with the controller, a power conversion circuit electrically connected with the pulse width modulation control circuit and used for receiving pulse signals sent by the pulse width modulation control circuit, and a current detection circuit electrically connected with the power conversion circuit. According to the scheme of the utility model, the speed control precision of the switched reluctance motor can be effectively improved.

Description

Technical Field

[0001] This utility model relates to the field of electric vehicle motor control technology, and in particular to a high-precision speed control system for switched reluctance motors for electric vehicles. Background Technology

[0002] In electric vehicle drive systems, switched reluctance motors (SRMs) are widely used due to their simple structure, low cost, and high reliability. However, current SRMs suffer from low speed control accuracy, primarily due to the unique structure of the motor itself and the limitations of traditional control strategies. The large torque ripple of SRMs causes significant speed fluctuations during operation, making high-precision speed control difficult. This low-precision speed control not only affects the smoothness and comfort of electric vehicle driving but also reduces motor efficiency, increases energy consumption, and consequently impacts the vehicle's driving range. Furthermore, the required speed control accuracy of SRMs is even higher during acceleration, deceleration, and various road conditions, but existing control systems struggle to meet these complex speed control demands. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a high-precision speed control system for switched reluctance motors for electric vehicles. By improving the drive control circuit, the speed control accuracy of the switched reluctance motor is effectively improved to meet the requirements of electric vehicles for precise speed control under various operating conditions, thereby improving the driving performance and energy efficiency of electric vehicles.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0005] A high-precision speed control system for a switched reluctance motor for electric vehicles includes:

[0006] A speed sensor electrically connected to the switched reluctance motor collects the actual rotor speed signal of the switched reluctance motor.

[0007] The controller is electrically connected to the speed sensor;

[0008] A drive control circuit electrically connected to the controller receives drive control commands sent by the controller based on the actual speed signal, and causes the drive control circuit to generate pulse signals according to the drive control commands, and controls the speed of the switched reluctance motor through the pulse signals;

[0009] The drive control circuit includes: a pulse width modulation control circuit electrically connected to the controller; a power conversion circuit electrically connected to the pulse width modulation control circuit and receiving pulse signals sent by the pulse width modulation control circuit; and a current detection circuit electrically connected to the power conversion circuit.

[0010] Optionally, the pulse width modulation control circuit includes:

[0011] First resistor, second resistor, third resistor, fourth resistor, fifth resistor, operational amplifier, first diode;

[0012] The first resistor, the second resistor, and the third resistor are all connected to the negative input terminal of the operational amplifier;

[0013] The negative bias voltage signal is input to the negative input terminal of the operational amplifier through the first resistor;

[0014] The control voltage signal is input to the negative input terminal of the operational amplifier through the second resistor;

[0015] The modulated voltage signal is input to the negative input terminal of the operational amplifier through the third resistor;

[0016] The fourth resistor is connected to the positive input terminal of the operational amplifier;

[0017] The operational amplifier outputs a pulse signal and is grounded through a fifth resistor. One end of the first diode is electrically connected to the output of the operational amplifier, and the other end is grounded.

[0018] Optionally, the power conversion circuit includes:

[0019] A first winding conversion circuit is electrically connected to the first phase winding of the switched reluctance motor and electrically connected to the power supply voltage through a first transistor;

[0020] The second winding conversion circuit is electrically connected to the first winding conversion circuit via a second transistor, and the second winding conversion circuit is electrically connected to the second winding of the switched reluctance motor.

[0021] A pulse circuit is provided corresponding to the first winding transformation circuit and the second winding transformation circuit.

[0022] Optionally, the first winding transformation circuit includes:

[0023] The components include a first coil, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second diode, a first transistor, and a third diode.

[0024] The first end of the first coil is electrically connected to the first transistor, and the second end is electrically connected to the first transistor through the sixth resistor and the second diode; the second end is electrically connected to the first end of the first capacitor, and the first capacitor is connected in series with the seventh resistor and then in parallel with the sixth resistor;

[0025] The first end of the eighth resistor is connected between the sixth resistor and the second diode, and the second end is electrically connected to the first transistor.

[0026] The first terminal of the first transistor is electrically connected to the first terminal of the eighth resistor, and the second and third terminals of the first transistor are electrically connected to the first transistor.

[0027] One end of the third diode is electrically connected to the first end of the first transistor, and the other end is electrically connected to the first transistor.

[0028] Optionally, the second winding conversion circuit includes:

[0029] The second coil, the second capacitor, the ninth resistor, the tenth resistor, the fourth diode, the second transistor, and the fifth diode;

[0030] The first end of the second coil is electrically connected to the second transistor, and the second end is electrically connected to the second transistor through the second capacitor, the ninth resistor, and the fourth diode.

[0031] The first end of the tenth resistor is connected between the ninth resistor and the fourth diode, and the second end is electrically connected to the second transistor.

[0032] The first terminal of the second transistor is electrically connected to the first terminal of the tenth resistor, and the second and third terminals of the second transistor are electrically connected to the second transistor.

[0033] One end of the fifth diode is electrically connected to the first end of the second transistor, and the other end is electrically connected to the second transistor.

[0034] Optionally, the pulse circuit includes:

[0035] A third coil, a third capacitor, a third transistor, a fourth transistor, a fourth capacitor, an eleventh resistor, and a twelfth resistor are provided corresponding to the first coil and the second coil;

[0036] The first end of the third coil is grounded, and the second end is connected between the third transistor and the fourth transistor through the third capacitor;

[0037] The first terminal of the third transistor is grounded through the fourth capacitor, the second terminal is electrically connected to the eleventh resistor, and the third terminal is electrically connected to the first terminal of the fourth transistor.

[0038] The second end of the fourth transistor is electrically connected to the twelfth resistor, the third end is electrically connected to the second end of the third coil and then grounded, and the eleventh resistor is electrically connected to the twelfth resistor.

[0039] Optionally, the current detection circuit includes: a first current detection circuit for detecting the current between the power supply and the winding load of the switched reluctance motor, and a second current detection circuit for detecting the current between the winding load of the switched reluctance motor and ground.

[0040] Optionally, the first current detection circuit includes:

[0041] The thirteenth resistor, the fourteenth resistor, the fifteenth resistor, the sixteenth resistor, the seventeenth resistor, the eighteenth resistor, the fifth transistor, the first differential amplifier, and the second differential amplifier;

[0042] Among them, one end of the thirteenth resistor is electrically connected to the power supply, and the other end is connected to the load;

[0043] The first end of the thirteenth resistor is electrically connected to the positive input terminal of the first differential amplifier through the fourteenth resistor;

[0044] The second end of the thirteenth resistor is electrically connected to the negative input terminal of the first differential amplifier through the fifteenth resistor;

[0045] The output terminal of the first differential amplifier is electrically connected to the positive input terminal of the second differential amplifier, and the positive input terminal of the second differential amplifier is grounded through the sixteenth resistor;

[0046] The negative input terminal of the second differential amplifier is grounded through the seventeenth resistor and electrically connected to the output terminal through the eighteenth resistor.

[0047] Optionally, the second current detection circuit includes:

[0048] The nineteenth resistor, the twentieth resistor, the twenty-first resistor, the twenty-second resistor, the twenty-third resistor, and the third differential amplifier;

[0049] The first end of the nineteenth resistor is electrically connected to the load, the second end is grounded, the first end is electrically connected to the positive input terminal of the third differential amplifier through the twentieth resistor, and the second end is electrically connected to the positive input terminal of the third differential amplifier through the twenty-first resistor.

[0050] The first end of the twentieth resistor is electrically connected to the load, and the second end is grounded through the twenty-second resistor.

[0051] The 21st resistor is electrically connected to the output terminal of the third differential amplifier through the 23rd resistor.

[0052] Optionally, the high-precision speed control system for switched reluctance motors for electric vehicles further includes: an overvoltage protection circuit, wherein the overvoltage protection circuit includes:

[0053] The twenty-fourth resistor, the twenty-fifth resistor, the twenty-sixth resistor, the fifth capacitor, the sixth diode, the seventh diode, and the sixth transistor;

[0054] Among them, the fifth capacitor and the sixth diode are connected in parallel, and then electrically connected to the sixth transistor through the twenty-fifth resistor;

[0055] The first end of the 24th resistor is electrically connected to the 6th diode and to the first end of the 25th resistor;

[0056] The output terminal of the sixth transistor is electrically connected to the seventh diode;

[0057] One end of the 26th resistor is electrically connected to the 7th diode via a switch, and the other end is grounded.

[0058] The above-described solution of this utility model has at least the following beneficial effects:

[0059] The above-described solution of this utility model acquires the actual rotational speed of the switched reluctance motor in real time through a speed sensor and feeds the speed signal back to the controller. The controller outputs a control signal to the drive control circuit. The drive control circuit generates corresponding drive pulses through a pulse width modulation control circuit. Through a power conversion circuit and a current detection circuit electrically connected to the power conversion circuit, the switched reluctance motor is precisely driven and controlled, thereby achieving high-precision adjustment of the motor speed. This effectively improves the speed control accuracy of the switched reluctance motor, meets the requirements of electric vehicles for precise motor speed control under various operating conditions, and enhances the driving performance and energy efficiency of electric vehicles. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the architecture of a high-precision speed control system for a switched reluctance motor for electric vehicles according to this utility model.

[0061] Figure 2 This is a schematic diagram of the pulse width modulation control circuit of this utility model;

[0062] Figure 3 This is a schematic diagram of the power conversion circuit of this utility model;

[0063] Figure 4 This is a schematic diagram of the first current detection circuit of this utility model;

[0064] Figure 5 This is a schematic diagram of the second current detection circuit of this utility model;

[0065] Figure 6This is a schematic diagram of the overvoltage protection circuit of this utility model;

[0066] Figure 7 This is a schematic diagram of the overcurrent protection circuit of this utility model. Detailed Implementation

[0067] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0068] like Figure 1 As shown, an embodiment of this utility model proposes a high-precision speed control system for a switched reluctance motor in electric vehicles, comprising:

[0069] A speed sensor electrically connected to the switched reluctance motor collects the actual rotor speed signal of the switched reluctance motor.

[0070] The controller is electrically connected to the speed sensor;

[0071] A drive control circuit electrically connected to the controller receives drive control commands sent by the controller based on the actual speed signal, and causes the drive control circuit to generate pulse signals according to the drive control commands, and controls the speed of the switched reluctance motor through the pulse signals;

[0072] The drive control circuit includes: a pulse width modulation control circuit electrically connected to the controller; a power conversion circuit electrically connected to the pulse width modulation control circuit and receiving pulse signals sent by the pulse width modulation control circuit; and a current detection circuit electrically connected to the power conversion circuit.

[0073] In this embodiment, the speed sensor collects the actual rotational speed of the rotor of the switched reluctance motor in real time and feeds the speed signal back to the controller. The controller outputs a control signal to the drive control circuit. The drive control circuit generates a corresponding drive pulse signal through the pulse width modulation control circuit. Through the power conversion circuit and the current detection circuit electrically connected to the power conversion circuit, the switched reluctance motor is precisely driven and controlled, thereby achieving high-precision adjustment of the motor speed. This effectively improves the speed control accuracy of the switched reluctance motor, meets the requirements of electric vehicles for precise motor speed control under various operating conditions, and improves the driving performance and energy efficiency of electric vehicles.

[0074] like Figure 2 As shown, in an optional embodiment of the present invention, the pulse width modulation control circuit includes:

[0075] The first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the operational amplifier A1, and the first diode D1;

[0076] The first resistor R1, the second resistor R2, and the third resistor R3 are all connected to the negative input terminal of the operational amplifier A1;

[0077] The negative bias voltage signal is input to the negative input terminal of the operational amplifier A1 through the first resistor R1;

[0078] The control voltage signal is input to the negative input terminal of the operational amplifier A1 through the second resistor R2;

[0079] The modulation voltage signal is input to the negative input terminal of the operational amplifier A1 through the third resistor R3;

[0080] The fourth resistor R4 is connected to the positive input terminal of the operational amplifier A1;

[0081] The output terminal of the operational amplifier A1 outputs a pulse signal, which is grounded through the fifth resistor R5. One end of the first diode D1 is electrically connected to the output terminal of the operational amplifier A1, and the other end is grounded.

[0082] In this embodiment, the modulation voltage signal Ut is a sawtooth wave. The output of this operational amplifier depends on the two extreme limits in the input direction, that is, the positive and negative of Uc - (Ut + Uf). When the control voltage Uc > Uc + Uf, the output of the operational amplifier A1 is at a low level. On the contrary, when Uc < Uc + Uf, the output of the operational amplifier is at a high level; a pulse signal matching the speed signal is output through the pulse width modulation control circuit to achieve high-precision speed control of the motor; in addition, the first diode D1 and the fifth resistor R5 form a switching circuit to output the pulse signal to the power conversion circuit.

[0083] In an optional embodiment of the present invention, the power conversion circuit includes:

[0084] A first winding conversion circuit that is electrically connected to the first-phase winding of the switched reluctance motor and is electrically connected to the power supply voltage through the first transistor M1;

[0085] A second winding conversion circuit that is electrically connected to the first winding conversion circuit through the second transistor M2. The second winding conversion circuit is electrically connected to the second winding of the switched reluctance motor;

[0086] Pulse circuits corresponding to the first winding conversion circuit and the second winding conversion circuit.

[0087] In this embodiment, the power conversion circuit, by having an independent first winding conversion circuit corresponding to each phase winding, can more flexibly control the on / off state and magnitude of the phase current, effectively reducing the harmonic content of the phase current, reducing torque ripple, and thus improving speed control accuracy. For example, when a phase winding of a switched reluctance motor is energized, by controlling the on / off sequence and timing of the power switches in the asymmetrical half-bridge power conversion unit, the rise and fall rates of the phase current can be precisely adjusted, enabling the motor to generate a smoother torque.

[0088] like Figure 3 As shown, in an optional embodiment of the present invention, the first winding conversion circuit includes: a first coil N1, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a first capacitor C1, a second diode D2, a first transistor VT1, and a third diode D3.

[0089] The first end of the first coil N1 is electrically connected to the first transistor M1, and the second end is electrically connected to the first transistor M1 through the sixth resistor R6 and the second diode D2; the second end is electrically connected to the first end of the first capacitor C1, and the first capacitor C1 is connected in series with the seventh resistor R7 and in parallel with the sixth resistor R6.

[0090] The first end of the eighth resistor R8 is connected between the sixth resistor R6 and the second diode D2, and the second end is electrically connected to the first transistor M1.

[0091] The first terminal of the first transistor VT1 is electrically connected to the first terminal of the eighth resistor R8, and the second and third terminals of the first transistor VT1 are electrically connected to the first transistor M1.

[0092] One end of the third diode D3 is electrically connected to the first end of the first transistor VT1, and the other end is electrically connected to the first transistor M1.

[0093] like Figure 3 As shown, in an optional embodiment of the present invention, the second winding conversion circuit includes:

[0094] The components include: second coil N2, second capacitor C2, ninth resistor R9, tenth resistor R10, fourth diode D4, second transistor VT2, and fifth diode D5.

[0095] The first end of the second coil N2 is electrically connected to the second transistor M2, and the second end is electrically connected to the second transistor M2 through the second capacitor C2, the ninth resistor R9 and the fourth diode D4.

[0096] The first end of the tenth resistor R10 is connected between the ninth resistor R9 and the fourth diode D4, and the second end is electrically connected to the second transistor M2.

[0097] The first terminal of the second transistor VT2 is electrically connected to the first terminal of the tenth resistor R10, and the second and third terminals of the second transistor VT2 are electrically connected to the second transistor M2.

[0098] One end of the fifth diode D5 is electrically connected to the first end of the second transistor VT2, and the other end is electrically connected to the second transistor M2.

[0099] like Figure 3 As shown, in an optional embodiment of the present invention, the pulse circuit includes:

[0100] The third coil N3, the third capacitor C3, the third transistor VT3, the fourth transistor VT4, the fourth capacitor C4, the eleventh resistor R11, and the twelfth resistor R12 are provided corresponding to the first coil N1 and the second coil N2.

[0101] The first end of the third coil N3 is grounded, and the second end is connected between the third transistor VT3 and the fourth transistor VT4 through the third capacitor C3;

[0102] The first terminal of the third transistor VT3 is grounded through the fourth capacitor C4, the second terminal is electrically connected to the eleventh resistor R11, and the third terminal is electrically connected to the first terminal of the fourth transistor VT4.

[0103] The second terminal of the fourth transistor VT4 is electrically connected to the twelfth resistor R12, and the third terminal is electrically connected to the second terminal of the third coil N3 and then grounded. The eleventh resistor R11 is electrically connected to the twelfth resistor R12.

[0104] In this embodiment, when the pulse output of VT1 and VT2 is high, VT1 is turned on, providing driving power for the MOSFET; when it is low, VT2 is turned on, and the energy stored in the capacitor provides a reverse pulse.

[0105] The two waveforms output by the pulse circuit are converted into complementary pulse signals by the conditioning circuit, thereby driving the MOSFET. When the driving pulse is positive, the MOSFET is turned on, and during this period, VT3 and VT4 are turned off, and the discharge circuit formed by them does not work. When the secondary pulse voltage is zero, VT3 and VT4 are turned on, rapidly discharging the gate charge of the MOSFET and accelerating the turn-off of the MOSFET.

[0106] In an optional embodiment of this utility model, the current detection circuit includes: a first current detection circuit for detecting the current between the power supply and the winding load of the switched reluctance motor, and a second current detection circuit for detecting the current between the winding load of the switched reluctance motor and ground.

[0107] like Figure 4As shown, in an optional embodiment of the present invention, the first current detection circuit includes: a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a fifth transistor VT5, a first differential amplifier AF1, and a second differential amplifier AF2.

[0108] Among them, one end of the thirteenth resistor R13 is electrically connected to the power supply, and the other end is connected to the load;

[0109] The first end of the thirteenth resistor R13 is electrically connected to the positive input terminal of the first differential amplifier AF1 through the fourteenth resistor R14.

[0110] The second end of the thirteenth resistor R13 is electrically connected to the negative input terminal of the first differential amplifier AF1 through the fifteenth resistor R15.

[0111] The output terminal of the first differential amplifier AF1 is electrically connected to the positive input terminal of the second differential amplifier AF2, and the positive input terminal of the second differential amplifier AF2 is grounded through the sixteenth resistor R16;

[0112] The negative input terminal of the second differential amplifier AF2 is grounded through the seventeenth resistor R17, and electrically connected to the voltage output terminal through the eighteenth resistor R18.

[0113] In this embodiment, the current is detected by measuring the voltage drop between the power supply and the motor load using a resistor and a differential amplifier. The resistor value used when the voltage drop is tens of mV to hundreds of mV is used, and the low resistor used for current detection has a small resistance value of less than a few Ω.

[0114] When detecting large currents of tens of A, extremely small resistance values ​​of several mΩ are required. Therefore, low-resistance metal plate and metal foil types, which are characterized by small resistance values, are commonly used. Small currents are detected by larger resistance values ​​of hundreds of mΩ to several Ω.

[0115] like Figure 5 As shown, in an optional embodiment of the present invention, the second current detection circuit includes:

[0116] The nineteenth resistor R19, the twentieth resistor R20, the twenty-first resistor R21, the twenty-second resistor R22, the twenty-third resistor R23, and the third differential amplifier AF3;

[0117] The first end of the nineteenth resistor R19 is electrically connected to the load, and the second end is grounded. The first end is electrically connected to the positive input terminal of the third differential amplifier AF3 through the twentieth resistor R20, and the second end is electrically connected to the positive input terminal of the third differential amplifier AF3 through the twenty-first resistor R21.

[0118] The first end of the twentieth resistor R20 is electrically connected to the load, and the second end is grounded through the twenty-second resistor R22;

[0119] The 21st resistor R21 is electrically connected to the output terminal of the 3rd differential amplifier AF3 through the 23rd resistor R23.

[0120] In this embodiment, the voltage drop between the load and ground is detected using relevant resistors and a differential amplifier to monitor the phase current in real time. The detected phase current signal is converted into a voltage signal and fed back to the pulse width modulation (PWM) control circuit. The PWM control circuit adjusts the drive pulses in real time based on the feedback current signal to ensure that the phase current always tracks the current command output by the controller. This closed-loop current control method effectively suppresses current fluctuations and further improves the speed control accuracy of the motor. For example, when the detected phase current exceeds a preset upper current limit, the PWM control circuit immediately reduces the duty cycle of the drive pulses, lowering the phase current and ensuring the stability and reliability of motor operation.

[0121] like Figure 6 As shown, an embodiment of the high-precision speed control system for switched reluctance motors for electric vehicles of this utility model further includes: an overvoltage protection circuit, the overvoltage protection circuit comprising:

[0122] The components are: the twenty-fourth resistor R24, the twenty-fifth resistor R25, the twenty-sixth resistor R26, the fifth capacitor C5, the sixth diode D6, the seventh diode D7, and the sixth transistor VT6.

[0123] Among them, the fifth capacitor C5 is connected in parallel with the sixth diode D6, and then electrically connected to the sixth transistor VT6 through the twenty-fifth resistor R25;

[0124] The first terminal of the 24th resistor R24 ​​is electrically connected to the sixth diode D6, and is also electrically connected to the first terminal of the 25th resistor R25.

[0125] The output terminal of the sixth transistor VT6 is electrically connected to the seventh diode D7;

[0126] One end of the 26th resistor R26 is electrically connected to the 7th diode D7 through a switch, and the other end is grounded.

[0127] In this embodiment, when the external voltage E does not exceed the set voltage Vs, the negative resistance LED D6 is cut off, VT6 is also cut off due to the lack of base current, relay J does not engage, and its normally closed contact K closes, supplying power to the load. Once the external voltage E exceeds the set voltage Vs, D6 changes from cutoff to conduction, and D6 illuminates to indicate overvoltage. The current flowing through D6 provides the base current for VT6, VT6 conducts, J engages, and the normally closed contact K opens, cutting off the power supply to the load and providing protection. When the external voltage E returns to below Vs, the reset button AN should be pressed to cut off D6 and VT6, release J, and restore power supply to the load. The capacitor C5 connected in parallel with D6 is for electromagnetic interference suppression and can be selected within the range of 0.01-0.1uF.

[0128] like Figure 7 As shown, an embodiment of the high-precision speed control system for switched reluctance motors for electric vehicles of this utility model further includes: an overcurrent protection circuit; the overcurrent protection circuit includes:

[0129] The components are: resistor R27 (twenty-seventh), resistor R28 (twenty-eighth), resistor R29 (twenty-ninth), resistor R30 (thirtieth), transistor VT6 (sixth), capacitor C6 (sixth), and thermistor PTC.

[0130] The first end of the twenty-seventh resistor R27 is electrically connected to the thermistor PTC, and the second end is electrically connected to the twenty-eighth resistor.

[0131] The input terminal of the sixth transistor VT6 is connected between the twenty-seventh resistor R27 and the twenty-eighth resistor;

[0132] The first end of the twenty-ninth resistor R29 is electrically connected to the thermistor PTC, and the second end is electrically connected to the second end of the sixth transistor VT6.

[0133] The third terminal of the sixth transistor VT6 is electrically connected to the thirtieth resistor R30, and the sixth capacitor C6 is connected in parallel with the thirtieth resistor R30 and grounded.

[0134] In this embodiment, the thermistor PTC reduces residual current by limiting the consumption of the entire circuit through its sudden resistance changes. When the circuit is in normal condition, the current through the thermistor PTC is less than the rated current, and the overcurrent protection thermistor PTC is in its normal state with a very low resistance, which does not affect the normal operation of the protected circuit. When a fault occurs in the circuit and the current greatly exceeds the rated current, the overcurrent protection thermistor PTC heats up suddenly, exhibiting a high resistance state, which puts the circuit in a relatively "open" state, thereby protecting the circuit from damage. After the fault is cleared, the overcurrent protection thermistor PTC automatically returns to a low resistance state, and the circuit resumes normal operation.

[0135] The above embodiments of this invention, by employing a power conversion circuit, effectively reduce torque ripple and current fluctuations in the switched reluctance motor, significantly improving speed control accuracy. Experimental tests show that, under various operating conditions, the speed control system of this invention can improve the speed control accuracy of the switched reluctance motor to within ±0.5%, which is more than 50% higher than that of traditional control systems, meeting the stringent requirements of electric vehicles for precise motor speed control.

[0136] High-precision speed control makes electric vehicles run more smoothly, with smoother acceleration and deceleration, effectively improving passenger comfort. At the same time, it reduces additional wear on the motor caused by speed fluctuations, extending the motor's lifespan.

[0137] Due to the improved speed control precision, the motor can operate at a more efficient point, reducing energy consumption and increasing the driving range of electric vehicles. Actual road tests have shown that electric vehicles using this new speed control system, under the same driving conditions, have an 8%-12% longer driving range compared to traditional control systems, demonstrating significant energy savings.

[0138] The protection circuit in the drive control circuit can protect the circuit and motor in a timely and effective manner, preventing system failures caused by abnormal conditions such as overvoltage, overcurrent and overheating, improving the reliability and stability of the entire speed control system and reducing the maintenance cost of electric vehicles.

[0139] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A high-precision speed control system for a switched reluctance motor for electric vehicles, characterized in that, include: A speed sensor electrically connected to the switched reluctance motor, the speed sensor acquiring the actual rotor speed signal of the switched reluctance motor; The controller is electrically connected to the speed sensor; A drive control circuit electrically connected to the controller receives drive control commands sent by the controller based on the actual speed signal, and causes the drive control circuit to generate pulse signals according to the drive control commands, and controls the speed of the switched reluctance motor through the pulse signals; The drive control circuit includes: a pulse width modulation control circuit electrically connected to the controller; a power conversion circuit electrically connected to the pulse width modulation control circuit and receiving pulse signals sent by the pulse width modulation control circuit; and a current detection circuit electrically connected to the power conversion circuit.

2. The high-precision speed control system for switched reluctance motors for electric vehicles according to claim 1, characterized in that, The pulse width modulation control circuit includes: First resistor (R1), second resistor (R2), third resistor (R3), fourth resistor (R4), fifth resistor (R5), operational amplifier (A1), first diode (D1); The first resistor (R1), the second resistor (R2), and the third resistor (R3) are all connected to the negative input terminal of the operational amplifier (A1); The negative bias voltage signal is input to the negative input terminal of the operational amplifier (A1) through the first resistor (R1); The control voltage signal is input to the negative input terminal of the operational amplifier (A1) through the second resistor (R2); The modulated voltage signal is input to the negative input terminal of the operational amplifier (A1) through the third resistor (R3); The fourth resistor (R4) is connected to the positive input terminal of the operational amplifier (A1); The operational amplifier (A1) outputs a pulse signal and is grounded through the fifth resistor (R5). One end of the first diode (D1) is electrically connected to the output of the operational amplifier (A1), and the other end is grounded.

3. The high-precision speed control system for switched reluctance motors for electric vehicles according to claim 1, characterized in that, The power conversion circuit includes: A first winding conversion circuit is electrically connected to the first phase winding of the switched reluctance motor and electrically connected to the power supply voltage through a first transistor (M1); The second winding conversion circuit is electrically connected to the first winding conversion circuit via the second transistor (M2), and the second winding conversion circuit is electrically connected to the second winding of the switched reluctance motor. A pulse circuit is provided corresponding to the first winding transformation circuit and the second winding transformation circuit.

4. The high-precision speed control system for switched reluctance motors for electric vehicles according to claim 3, characterized in that, The first winding conversion circuit includes: The first coil (N1), the sixth resistor (R6), the seventh resistor (R7), the eighth resistor (R8), the first capacitor (C1), the second diode (D2), the first transistor (VT1), and the third diode (D3); The first end of the first coil (N1) is electrically connected to the first transistor (M1), and the second end is electrically connected to the first transistor (M1) through the sixth resistor (R6) and the second diode (D2); the second end is electrically connected to the first end of the first capacitor (C1), and the first capacitor (C1) is connected in series with the seventh resistor (R7) and then in parallel with the sixth resistor (R6); The first end of the eighth resistor (R8) is connected between the sixth resistor (R6) and the second diode (D2), and the second end is electrically connected to the first transistor (M1); The first terminal of the first transistor (VT1) is electrically connected to the first terminal of the eighth resistor (R8), and the second and third terminals of the first transistor (VT1) are electrically connected to the first transistor (M1). One end of the third diode (D3) is electrically connected to the first end of the first transistor (VT1), and the other end is electrically connected to the first transistor (M1).

5. The high-precision speed control system for switched reluctance motors for electric vehicles according to claim 4, characterized in that, The second winding conversion circuit includes: The second coil (N2), the second capacitor (C2), the ninth resistor (R9), the tenth resistor (R10), the fourth diode (D4), the second transistor (VT2), and the fifth diode (D5); The first end of the second coil (N2) is electrically connected to the second transistor (M2), and the second end is electrically connected to the second transistor (M2) through the second capacitor (C2), the ninth resistor (R9) and the fourth diode (D4); The first end of the tenth resistor (R10) is connected between the ninth resistor (R9) and the fourth diode (D4), and the second end is electrically connected to the second transistor (M2); The first terminal of the second transistor (VT2) is electrically connected to the first terminal of the tenth resistor (R10), and the second and third terminals of the second transistor (VT2) are electrically connected to the second transistor (M2). One end of the fifth diode (D5) is electrically connected to the first end of the second transistor (VT2), and the other end is electrically connected to the second transistor (M2).

6. The high-precision speed control system for switched reluctance motors for electric vehicles according to claim 5, characterized in that, The pulse circuit includes: A third coil (N3), a third capacitor (C3), a third transistor (VT3), a fourth transistor (VT4), a fourth capacitor (C4), an eleventh resistor (R11), and a twelfth resistor (R12) are provided corresponding to the first coil (N1) and the second coil (N2); The first end of the third coil (N3) is grounded, and the second end is connected between the third transistor (VT3) and the fourth transistor (VT4) through the third capacitor (C3); The first terminal of the third transistor (VT3) is grounded through the fourth capacitor (C4), the second terminal is electrically connected to the eleventh resistor (R11), and the third terminal is electrically connected to the first terminal of the fourth transistor (VT4). The second terminal of the fourth transistor (VT4) is electrically connected to the twelfth resistor (R12), and the third terminal is electrically connected to the second terminal of the third coil (N3) and then grounded. The eleventh resistor (R11) is electrically connected to the twelfth resistor (R12).

7. The high-precision speed control system for switched reluctance motors for electric vehicles according to claim 1, characterized in that, The current detection circuit includes: a first current detection circuit for detecting the current between the power supply and the winding load of the switched reluctance motor, and a second current detection circuit for detecting the current between the winding load of the switched reluctance motor and ground.

8. The high-precision speed control system for switched reluctance motors for electric vehicles according to claim 7, characterized in that, The first current detection circuit includes: The thirteenth resistor (R13), the fourteenth resistor (R14), the fifteenth resistor (R15), the sixteenth resistor (R16), the seventeenth resistor (R17), the eighteenth resistor (R18), the fifth transistor (VT5), the first differential amplifier (AF1), and the second differential amplifier (AF2); Among them, one end of the thirteenth resistor (R13) is electrically connected to the power supply, and the other end is connected to the load; The first terminal of the thirteenth resistor (R13) is electrically connected to the positive input terminal of the first differential amplifier (AF1) through the fourteenth resistor (R14); The second end of the thirteenth resistor (R13) is electrically connected to the negative input terminal of the first differential amplifier (AF1) through the fifteenth resistor (R15); The output terminal of the first differential amplifier (AF1) is electrically connected to the positive input terminal of the second differential amplifier (AF2), and the positive input terminal of the second differential amplifier (AF2) is grounded through the sixteenth resistor (R16); The negative input terminal of the second differential amplifier (AF2) is grounded through the seventeenth resistor (R17), and electrically connected to the output terminal through the eighteenth resistor (R18).

9. The high-precision speed control system for switched reluctance motors for electric vehicles according to claim 7, characterized in that, The second current detection circuit includes: The nineteenth resistor (R19), the twentieth resistor (R20), the twenty-first resistor (R21), the twenty-second resistor (R22), the twenty-third resistor (R23), and the third differential amplifier (AF3); The first end of the nineteenth resistor (R19) is electrically connected to the load, and the second end is grounded. The first end is electrically connected to the positive input terminal of the third differential amplifier (AF3) through the twentieth resistor (R20), and the second end is electrically connected to the positive input terminal of the third differential amplifier (AF3) through the twenty-first resistor (R21). The first end of the twentieth resistor (R20) is electrically connected to the load, and the second end is grounded through the twenty-second resistor (R22); The 21st resistor (R21) is electrically connected to the output terminal of the third differential amplifier (AF3) through the 23rd resistor (R23).

10. The high-precision speed control system for switched reluctance motors for electric vehicles according to claim 1, characterized in that, Also includes: Overvoltage protection circuit, the overvoltage protection circuit includes: The twenty-fourth resistor (R24), the twenty-fifth resistor (R25), the twenty-sixth resistor (R26), the fifth capacitor (C5), the sixth diode (D6), the seventh diode (D7), and the sixth transistor (VT6); Among them, the fifth capacitor (C5) and the sixth diode (D6) are connected in parallel, and then electrically connected to the sixth transistor (VT6) through the twenty-fifth resistor (R25); The first terminal of the 24th resistor (R24) is electrically connected to the sixth diode (D6) and to the first terminal of the 25th resistor (R25); The output terminal of the sixth transistor (VT6) is electrically connected to the seventh diode (D7); One end of the 26th resistor (R26) is electrically connected to the 7th diode (D7) via a switch, and the other end is grounded.

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