High-voltage power supply driven low-inductance high-speed motor system and control method

Abstract

The invention belongs to the field of motor control, and particularly discloses a control method for driving a low-inductance high-speed motor by a high-voltage power supply. The software part comprises a commutation module, a bidirectional DC / DC conversion module, a brake module, a rotating speed PI controller and a voltage PI controller, the hardware part is provided with a Hall sensor and a low-inductance high-speed brushless direct current motor, and the commutation module realizes six-step commutation of the brushless direct current motor; the bidirectional DC / DC conversion module is used for realizing a step-down speed regulation function when the motor is driven, and realizing a step-up energy backflow function when the motor reversely generates power; the brake module realizes the functions of voltage limiting and energy storage when the motor reversely generates power; the rotating speed PI controller compares the actual motor rotating speed with a rotating speed reference value and generates a direct-current voltage reference value; the voltage PI controller compares the measured bus DC voltage with a voltage reference value, generates a required duty ratio through modulation, and outputs the duty ratio to the DC / DC module; and the Hall sensor realizes acquisition and feedback of the rotor position.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a high-voltage power supply driving a low-inductance high-speed motor system and a control method. Background Art

[0002] Brushless DC motors are increasingly being used in aviation power-by-wire control systems due to their simple structure, high efficiency, small size, and good control performance. In particular, they have played an important role in promoting modern aircraft to be more efficient, safe, and lightweight. Common control methods for brushless DC motors include six-step commutation control, field-oriented control, and sinusoidal wave control. Six-step commutation control is widely used because of its simple control algorithm, low hardware cost, and ability to achieve higher motor speeds. However, for high-speed, low-inductance motors driven by high-voltage power supplies, traditional six-step commutation control applies PWM pulse width modulation waveforms to the switch tubes of the three-phase converter of the DC motor. Due to the excessively high bus voltage and the low-inductance and high-speed characteristics of the DC motor, the following problems may occur:

[0003] (1) The switches of the three-phase converter will have a higher switching frequency, and the current waveform will replicate the voltage waveform of the PWM. Such a current waveform will magnetize and demagnetize the metal quickly and frequently, causing huge heat losses due to hysteresis.

[0004] (2) Skin effect of current. In high-speed low-inductance motors and high-voltage bus systems, the skin effect will be enhanced due to high-frequency voltage and current changes, causing the current flowing in the conductor to be concentrated in the surface area, thereby increasing the equivalent resistance of the conductor and causing greater losses and heat.

[0005] (3) Eddy current loss of magnetic field: When the motor is running at high speed, eddy currents will be generated in the core material of the motor stator or rotor, especially when the inductance is low and the frequency of magnetic field change is high. These eddy currents will cause additional energy loss,

[0006] It manifests as heat generation, reduces system efficiency, and may accelerate material aging;

[0007] (4) Overvoltage and insulation stress. In high-voltage bus systems, transient overvoltages are generated when motors start and stop. Low-inductance motors may be more susceptible to these overvoltages due to the lack of buffering against voltage surges.

[0008] Therefore, for the control method of a high-voltage power supply driving a low-inductance high-speed motor, the existing traditional six-step commutation control method cannot produce a good control effect. Summary of the invention

[0009] In view of the deficiencies in the prior art, the main purpose of the present invention is to provide a high-voltage power supply driven low-inductance high-speed motor system and control method, aiming to reduce the switching frequency of the three-phase inverter switch tube when the high-voltage power supply controls the low-inductance high-speed brushless DC motor, and improve the control performance of the motor through a six-step commutation method.

[0010] The complete technical solution of the present invention includes:

[0011] A high-voltage power supply driving a low-inductance high-speed motor system, comprising a commutation module, a bidirectional DC / DC conversion module, a braking module, a speed PI controller, a voltage PI controller and a Hall sensor;

[0012] The commutation module is used to realize six-step commutation of the motor;

[0013] The bidirectional DC / DC conversion module realizes motor speed regulation by adjusting the voltage;

[0014] The brake module is used to achieve voltage limiting and energy recovery when the motor generates reverse power;

[0015] The Hall sensor determines the rotor position and the direction of motor rotation;

[0016] The speed PI controller compares the actual motor speed with the speed reference value and generates a DC voltage reference value. The voltage PI controller compares the measured bus DC voltage with the voltage reference value, generates the required duty cycle through modulation and outputs it to the bidirectional DC / DC module. The bidirectional DC / DC module adjusts the speed by changing the DC voltage connected to the three-phase inverter according to the voltage amplitude being proportional to the motor speed. At the same time, according to the rotor position and motor rotation direction determined by the Hall sensor, the on and off of the commutation module switch tube is controlled to generate an appropriate pulse signal to control the motor rotation. At the same time, when the motor generates electricity in reverse, the effect of charging and energy storage is achieved.

[0017] Furthermore, the commutation module includes 6 switching tubes, namely, A-phase upper bridge arm switching tube A_T, A-phase lower bridge arm switching tube A_B, B-phase upper bridge arm switching tube B_T, B-phase lower bridge arm switching tube B_B, C-phase upper bridge arm switching tube C_T, and C-phase lower bridge arm switching tube C_B. The midpoints of the three groups of upper and lower bridge arms respectively draw out the three-phase current of the motor; the commutation module controls the six-step commutation through six fully opened or closed switching tubes.

[0018] Furthermore, the bidirectional DC / DC conversion module includes an upper bridge arm switch tube DCDC_T, a lower bridge arm switch tube DCDC_B, an inductor L and a capacitor C. The midpoints of the upper and lower bridge arms are connected to the inductor L and the phase-changing module, and the capacitor C is connected in parallel at both ends of the lower bridge arm switch tube DCDC_B. The bidirectional DC / DC conversion module switches the switch tube DCDC_T and uses the inductor L and the capacitor C to keep the output voltage at a desired level.

[0019] Furthermore, the braking module includes a switch tube Brake, and a resistor (or energy storage mechanism) and a diode in parallel; when a higher voltage appears during reverse power generation, the switch tube Brake of the braking module is closed, and energy is consumed by heat release through the resistor or absorbed by the energy storage mechanism, thereby reducing the voltage to a safe level.

[0020] Furthermore, the system implements a method for driving a low-inductance high-speed motor with a high-voltage power supply. The phase-changing module fully opens or closes 6 switching tubes without PWM modulation voltage to achieve a 100% duty cycle phase-changing function; and cooperates with a bidirectional DC / DC conversion module to achieve a motor speed regulation function.

[0021] Furthermore, three Hall sensors detect the rotor position information. When the Hall and the motor rotor make relative motion, they will generate changing signals as the rotor electromagnetic density changes, which are recorded as 1 and 0. When the motor rotates in a certain direction, the three Hall sensors will change according to the six-step rule. At the same time, combined with the six-step commutation control method, each Hall signal corresponds to a motor control step, so that the motor can rotate forward and reverse.

[0022] Furthermore, when the drive motor rotates, the voltage at the bus terminal is reduced through the bidirectional DC / DC conversion module, specifically: when the upper bridge arm DCDC_T switch tube is turned on, the lower bridge arm DCDC_B switch tube is turned off, the inductor limiting current gradually increases, the output voltage gradually increases, and the inductor L stores energy at the same time; when the output voltage is greater than the voltage required to control the speed, the upper bridge arm DCDC_T switch tube is immediately turned off, the lower bridge arm DCDC_B switch tube is turned on, and the inductor L is powered, and the inductor power supply gradually decreases. When the inductor power supply is lower than the voltage required to control the speed, the upper bridge arm DCDC_T switch tube is turned on again to supply power and charge the inductor; this process is repeated, and the energy storage and release of the inductor are controlled by controlling the on and off of the switch tube, thereby achieving voltage reduction;

[0023] When the upper bridge arm DCDC_T switch tube is disconnected and the lower bridge arm DCDC_B switch tube is turned on, the capacitor C supplies power to the circuit.

[0024] Furthermore, when working in reverse, boosting is achieved through the bidirectional DC / DC conversion module, that is, in the power generation state, energy can be transmitted back to the input bus end. Specifically, when the upper bridge arm DCDC_T switch tube is disconnected, the lower bridge arm DCDC_B switch tube is turned on, and the inductor L is charged. At the moment when the lower bridge arm DCDC_B switch tube is disconnected, the upper bridge arm DCDC_T is turned on, and the accumulated energy in the inductor L is transmitted to the DC bus end, plus the motor end voltage, to achieve the boost effect.

[0025] Furthermore, when the capacitor at the input end cannot absorb all the energy, thereby causing the voltage at the input end to be higher, the Brake switch tube of the brake module is turned on, and the resistor in the brake module is used to consume the excess energy.

[0026] Furthermore, when the capacitor at the input end cannot absorb all the energy, resulting in a higher voltage at the input end, the Brake switch tube of the brake module is turned on, and the energy storage element connected to the brake module is used to recover this part of the energy.

[0027] Compared with the prior art, the present invention mainly realizes the six-step phase change of the motor in the phase change module without PWM modulation. It only realizes the six-step phase change of the motor with 100% duty cycle phase change function by fully opening or closing the six switch tubes, thereby controlling the rotation of the motor. The bidirectional DC / DC conversion module realizes motor speed regulation by adjusting the voltage, which greatly reduces the switching frequency of the switch tube of the phase change module. The negative impact of the high switching frequency caused by the high-voltage power supply driving the low-inductance high-speed motor mentioned above is avoided. The brake module realizes voltage limiting and energy recovery when the motor generates electricity in reverse. During reverse operation, a higher voltage will appear. The switch tube Brake of the brake module can be closed to dissipate heat through resistance to consume energy and reduce the voltage to a safe level. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a topological diagram of a high-voltage power supply driving a low-inductance high-speed motor driving circuit of the present invention.

[0029] Figure 2 This is the traditional six-step PWM modulation output waveform.

[0030] Figure 3 This is the output waveform diagram of the low-inductance high-speed motor commutation module driven by the high-voltage power supply of the present invention.

[0031] Figure 4 This is the overall control block diagram of the high-voltage power supply driving the low-inductance high-speed motor of the present invention.

[0032] Figure 5 It is a waveform diagram of the control effect of simulating a low-inductance high-speed motor driven by a high-voltage power supply of the present invention. DETAILED DESCRIPTION

[0033] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0034] like Figure 1 As shown, it is the topology diagram of the high-voltage power supply driving low-inductance high-speed motor driving circuit of the present invention.

[0035] The control method of the high-voltage power supply driving a low-inductance high-speed motor of the present invention mainly includes three implementation modules: a phase-changing module, a bidirectional DC / DC conversion module and a braking module. The phase-changing module mainly realizes the six-step phase-changing of the motor, the bidirectional DC / DC conversion module realizes the motor speed regulation by adjusting the voltage, and the braking module realizes the voltage limiting and energy recovery when the motor generates reverse power.

[0036] The commutation module includes 6 switch tubes, namely, A-phase upper bridge arm switch tube A_T, A-phase lower bridge arm switch tube A_B, B-phase upper bridge arm switch tube B_T, B-phase lower bridge arm switch tube B_B, C-phase upper bridge arm switch tube C_T, C-phase lower bridge arm switch tube C_B, and the midpoint of the upper and lower bridge arms leads out the three-phase current of the motor. The commutation module controls the six-step commutation by six fully opened or closed switch tubes.

[0037] The bidirectional DC / DC conversion module includes two switch tubes, one inductor and one capacitor, which are the upper bridge arm switch tube DCDC_T and the lower bridge arm switch tube DCDC_B. The midpoints of the upper and lower bridge arms are connected to the inductor L and the phase-changing module, and the capacitor C is connected in parallel to both ends of the lower bridge arm switch tube. The bidirectional DC / DC conversion module uses the inductor L and the capacitor C to maintain the output voltage at the required level by switching the switch tube DCDC_T.

[0038] The brake module includes a switch tube and a resistor in parallel with a diode. Because the control method can work in reverse power generation, a higher voltage may occur during reverse operation, and the switch tube Brake of the brake module can be closed to dissipate heat and consume energy through the resistor to reduce the voltage to a safe level.

[0039] When driving the motor, the present invention can realize voltage reduction of the high-voltage bus system through the bidirectional DC / DC conversion module, and the six switch tubes in the phase-change module are fully opened or closed, and only the six-step phase change of the motor is realized, thereby controlling the rotation of the motor. When generating electricity in the reverse direction, energy can be transmitted to the power supply, and the brake module is used to limit the voltage to keep the voltage at a safe level.

[0040] According to the motor formula Due to the low inductance motor and when the motor is in steady state, Almost zero, according to the motor design principle, it is very small and can be ignored, so the formula can be simplified to:

[0041] If the motor speed is directly proportional to the voltage, the high-voltage bus system can reduce the voltage through the bidirectional DC / DC conversion module, directly control the motor speed change through the voltage change, and the six switching tubes of the commutation module are fully opened or closed to realize the six-step commutation of the motor.

[0042] From the above analysis, the motor speed is directly proportional to the voltage. When the drive motor rotates, the bus terminal voltage is reduced through the bidirectional DC / DC conversion module. The specific implementation method is that when the upper bridge arm DCDC_T switch tube is turned on and the lower bridge arm DCDC_B switch tube is turned off, the inductor limiting current gradually increases, the voltage at the output end gradually increases, and the inductor stores energy at the same time. When the output voltage is greater than the voltage required to control the speed, the upper bridge arm DCDC_T switch tube is immediately disconnected, and the lower bridge arm DCDC_B switch tube is turned on, and the inductor is powered. The inductor power supply will gradually decrease. When the inductor power supply is lower than the voltage required to control the speed, the upper bridge arm DCDC_T switch tube is turned on again to supply power and charge the inductor. This process is repeated, and the energy storage and release of the inductor are controlled by controlling the on and off of the switch tube, thereby achieving voltage reduction. The upper bridge arm DCDC_T switch tube is turned off and the lower bridge arm DCDC_B switch tube is turned on. Due to the reversal of the polarity of the inductor, the inductor cannot power the circuit at this moment, and the capacitor powers the circuit at this time. The characteristic of capacitors is that they discharge when the voltage on both sides is higher than the voltage of the external circuit, and charge when it is lower. According to the volt-second principle, VIN*D=VOUT, the duty cycle is directly related to the input and output voltages. The lower the control duty cycle, the lower the output voltage.

[0043] The present invention can also realize reverse operation, and realize boosting through a bidirectional DC / DC conversion module, that is, in the power generation state, energy can be transmitted back to the input bus terminal. The specific implementation method is that when the upper bridge arm DCDC_T switch tube is disconnected, the lower bridge arm DCDC_B switch tube is turned on, and the inductor is charged. At the moment when the lower bridge arm DCDC_B switch tube is disconnected, the upper bridge arm DCDC_T is turned on, and the accumulated energy in the inductor is transmitted to the DC bus terminal, plus the motor terminal voltage, to achieve the effect of boosting. For such operation for a long time, the capacitor at the input end will not absorb all the energy, which will cause the input end voltage to be higher. At this time, the Brake switch tube of the brake module must be turned on when the voltage is high, and the resistor in the brake module is used to consume the excess energy. In addition, energy storage elements, such as power supplies, can also be connected to the brake module to recover this part of the energy.

[0044] Compared with the traditional six-step commutation drive DC motor, each switch tube of the commutation module of the present invention can be fully opened or fully closed, without PWM modulation voltage, and only commutation function. Figure 2The figure shows a traditional six-step commutation drive DC motor. Each switch tube performs PWM modulation. Taking the H_PWM-L_PWM type as an example, in the 120° conduction interval, both the upper and lower bridge arms use PWM modulation. In this control method, when a high-voltage power supply drives a low-inductance high-speed motor, the switch tube will have a higher switching frequency, resulting in a series of negative effects listed above, affecting the motor control accuracy. Figure 3 The control method of the present invention is shown. Each switch tube of the commutation module does not perform PWM modulation, but is fully opened or closed to achieve a 100% duty cycle commutation function, and at the same time cooperates with the bidirectional DC / DC conversion module to achieve the motor speed regulation function. The control method of the present invention greatly reduces the switching frequency of the switch tube of the commutation module. Avoid the negative impact of the high switching frequency caused by the high voltage power supply driving the low inductance high-speed motor.

[0045] The basic principle of the six-step commutation of the motor is to generate a six-step voltage signal from the three phases A, B, and C, and use the principle of interaction between the energized coil and the permanent magnet to control the rotation of the motor. The specific implementation method of the commutation function is to use a three-phase full-bridge inverter circuit, each bridge arm has two switch tubes, such as Figure 1 As shown, controlling the on and off of these six switch tubes can realize the rotation of the motor with a six-beat voltage signal, which is a six-step commutation control method. However, only by knowing the rotor position information accurately can we accurately determine how to give the voltage signal. The present invention detects the rotor position information by three Hall sensors. When the Hall and the motor rotor make relative motion, a changing signal will be generated as the electromagnetic density of the rotor changes, which is recorded as 1 and 0. When the motor rotates in a certain direction, the three Hall sensors will change according to the six-step rule. At the same time, combined with the above-mentioned six-step commutation control method, each Hall signal corresponds to a control step of the motor, so that the motor can be reversed, and a high-voltage power supply can be made to drive a low-inductance high-speed motor forward and reverse conversion phase control logic table as shown in Table 1 and Table 2.

[0046] As shown in Table 1, it is a control logic table of the positive conversion phase of the low inductance high-speed motor driven by the high-voltage power supply of the present invention. When the Hall sensor signal is detected to be a certain value, the switch states corresponding to the six bridge arms are controlled. In order to realize the forward rotation of the motor, the signals of Hall 1, Hall 2, and Hall 3 are detected to be 1, 0, and 1 respectively. Then we should control the conduction of A_T and B_B bridge arms. When A_T and B_B bridge arms are turned on, the rotor of the motor will rotate toward a position. Before the rotation reaches the target position, the signal of the Hall sensor will change. At this time, the signals of Hall 1, Hall 2, and Hall 3 are 0, 0, and 1 respectively. At this time, the B_B bridge arm is immediately closed and the C_B bridge arm is opened. That is, A_T and C_B bridge arms are turned on at this moment, and other bridge arms are disconnected. In this way, the motor can rotate forward. Reverse, the principle is the same. Table 2 is a control logic table of the reverse conversion phase of the low inductance high-speed motor driven by the high-voltage power supply of the present invention.

[0047] Table 1. The positive conversion phase control logic table of the high voltage power supply driving the low inductance high speed motor of the present invention

[0048] Hall 1 Hall 2 Hall 3 A_T A_B B_T B_B C_T C_B 1 0 1 ON OFF OFF ON OFF OFF 0 0 1 ON OFF OFF OFF OFF ON 0 1 1 OFF OFF ON OFF OFF ON 0 1 0 OFF ON ON OFF OFF OFF 1 1 0 OFF ON OFF OFF ON OFF 1 0 0 OFF OFF OFF ON ON OFF

[0049] Table 2 The reverse phase control logic table of the high voltage power supply driving the low inductance high speed motor of the present invention

[0050] Hall 1 Hall 2 Hall 3 A_T A_B B_T B_B C_T C_B 1 0 1 OFF ON ON OFF OFF OFF 0 0 1 OFF ON OFF OFF ON OFF 0 1 1 OFF OFF OFF ON ON OFF 0 1 0 ON OFF OFF ON OFF OFF 1 1 0 ON OFF OFF OFF OFF ON 1 0 0 OFF OFF ON OFF OFF ON

[0051] Figure 4 This is the overall control block diagram of the high-voltage power supply driving a low-inductance high-speed motor of the present invention. The main components of the control system include a speed PI controller, a voltage PI controller, a brake module, a DC / DC module, a commutation module, a Hall sensor, etc. The speed PI controller compares the actual motor speed with the speed reference value and generates a DC voltage reference value. The voltage PI controller compares the measured bus DC voltage with the voltage reference value, generates the required duty cycle through modulation and outputs it to the DC / DC module. Due to the above analysis, the voltage amplitude of the DC / DC module is proportional to the motor speed, so the speed can be adjusted by changing the DC voltage connected to the three-phase inverter. At the same time, according to the rotor position and the direction of rotation of the motor determined by the Hall sensor, the on and off of the switch tube of the commutation module is controlled to generate an appropriate pulse signal to control the rotation of the motor. At the same time, based on the structure of the present invention, that is, the brake module and the DC / DC module, when the motor generates electricity in reverse, the effect of charging and energy storage can be achieved.

[0052] Figure 5 This is a waveform diagram of the control effect of the high-voltage power supply driving a low-inductance high-speed motor simulation of the present invention. Initially, the motor runs at a speed of 4000rpm without load. At 0.15s, a load torque of 0.5Nm is applied to the motor, and the control system increases the DC voltage reference value to maintain the motor speed at 4000rpm. At 0.3s, the speed reference value is reduced to 1500rpm, and the control system significantly reduces the DC voltage reference value to maintain system stability, while the frequency of the motor phase current is reduced.

[0053] The above applications are only some implementation methods of the present application. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A high voltage power supply driving a low inductance high speed motor system, characterized in that: It includes a commutation module, a bidirectional DC / DC conversion module, a braking module, a speed PI controller, a voltage PI controller and a Hall sensor; The commutation module is used to realize six-step commutation of the motor; The bidirectional DC / DC conversion module realizes motor speed regulation by adjusting the voltage; The brake module is used to achieve voltage limiting and energy recovery when the motor generates reverse power; The Hall sensor determines the rotor position and the direction of motor rotation; The speed PI controller compares the actual motor speed with the speed reference value and generates a DC voltage reference value. The voltage PI controller compares the measured bus DC voltage with the voltage reference value, generates the required duty cycle through modulation and outputs it to the bidirectional DC / DC module. The bidirectional DC / DC module adjusts the speed by changing the DC voltage connected to the three-phase inverter according to the voltage amplitude being proportional to the motor speed. At the same time, according to the rotor position and motor rotation direction determined by the Hall sensor, the on and off of the commutation module switch tube is controlled to generate an appropriate pulse signal to control the motor rotation. At the same time, when the motor generates electricity in reverse, the effect of charging and energy storage is achieved.

2. A high-voltage power supply driving low-inductance high-speed motor system according to claim 1, characterized in that: The commutation module includes 6 switching tubes, namely, A-phase upper bridge arm switching tube A_T, A-phase lower bridge arm switching tube A_B, B-phase upper bridge arm switching tube B_T, B-phase lower bridge arm switching tube B_B, C-phase upper bridge arm switching tube C_T, and C-phase lower bridge arm switching tube C_B. The midpoints of the three groups of upper and lower bridge arms respectively draw out the three-phase current of the motor; the commutation module controls the six-step commutation through six fully opened or closed switching tubes.

3. A high-voltage power supply driving low-inductance high-speed motor system according to claim 2, characterized in that: The bidirectional DC / DC conversion module includes an upper bridge arm switch tube DCDC_T, a lower bridge arm switch tube DCDC_B, an inductor L and a capacitor C. The midpoints of the upper and lower bridge arms are connected to the inductor L and the phase-changing module, and the capacitor C is connected in parallel to both ends of the lower bridge arm switch tube DCDC_B. The bidirectional DC / DC conversion module uses the inductor L and the capacitor C to maintain the output voltage at a desired level by switching the switch tube DCDC_T.

4. A high-voltage power supply driving low-inductance high-speed motor system according to claim 3, characterized in that: The braking module includes a switch tube Brake, a resistor or an energy storage mechanism, and a diode, wherein the resistor or the energy storage mechanism is connected in parallel with the diode; when a high voltage appears during reverse power generation, the switch tube Brake of the braking module is closed, and energy is consumed by heat release through the resistor or absorbed by the energy storage mechanism, thereby reducing the voltage to a safe level.

5. A method for driving a low-inductance high-speed motor with a high-voltage power supply using the system of claim 4, characterized in that: The commutation module realizes a 100% duty cycle commutation function by fully opening or closing the six switch tubes without PWM modulation voltage; and cooperates with the bidirectional DC / DC conversion module to realize the motor speed regulation function.

6. The method for driving a low-inductance high-speed motor with a high-voltage power supply according to claim 5, characterized in that: Three Hall sensors detect the rotor position information. When the Hall and the motor rotor make relative motion, they will generate changing signals as the rotor electromagnetic density changes, which are recorded as 1 and 0. When the motor rotates in a certain direction, the three Hall sensors will change according to the six-step rule. At the same time, combined with the six-step commutation control method, each Hall signal corresponds to a motor control step, so that the motor can rotate forward and reverse.

7. The method for driving a low-inductance high-speed motor with a high-voltage power supply according to claim 6, characterized in that: When the drive motor rotates, the voltage at the bus terminal is stepped down through the bidirectional DC / DC conversion module. Specifically, when the upper bridge arm DCDC_T switch tube is turned on and the lower bridge arm DCDC_B switch tube is turned off, the inductor limiting current gradually increases, the voltage at the output end gradually increases, and the inductor L stores energy at the same time; when the output voltage is greater than the voltage required to control the speed, the upper bridge arm DCDC_T switch tube is immediately turned off, and the lower bridge arm DCDC_B switch tube is turned on, and the inductor L is powered. The inductor power supply gradually decreases. When the inductor power supply is lower than the voltage required to control the speed, the upper bridge arm DCDC_T switch tube is turned on again to supply power and charge the inductor. This process is repeated over and over again, and the energy storage and release of the inductor are controlled by controlling the conduction and disconnection of the switch tube, thereby achieving voltage reduction; When the upper bridge arm DCDC_T switch tube is disconnected and the lower bridge arm DCDC_B switch tube is turned on, the capacitor C supplies power to the circuit.

8. The method for driving a low-inductance high-speed motor with a high-voltage power supply according to claim 7, characterized in that: When working in reverse, boosting is achieved through the bidirectional DC / DC conversion module, that is, in the power generation state, energy can be transferred back to the input bus end. Specifically, when the upper bridge arm DCDC_T switch tube is disconnected, the lower bridge arm DCDC_B switch tube is turned on, and the inductor L is charged. At the moment when the lower bridge arm DCDC_B switch tube is disconnected, the upper bridge arm DCDC_T is turned on, and the accumulated energy in the inductor L is transmitted to the DC bus end, plus the motor end voltage, to achieve the boost effect.

9. The method for driving a low-inductance high-speed motor with a high-voltage power supply according to claim 8, characterized in that: When the capacitor at the input end cannot absorb all the energy, resulting in a higher voltage at the input end, the brake switch tube of the brake module is turned on and the resistor in the brake module is used to consume the excess energy.

10. The method for driving a low-inductance high-speed motor with a high-voltage power supply according to claim 8, characterized in that: When the capacitor at the input end cannot absorb all the energy, resulting in a higher voltage at the input end, the Brake switch tube of the brake module is turned on, and the energy storage element connected to the brake module is used to recover this part of the energy.

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