Motor position and rotating speed acquisition device and method, chip and electrical equipment

Abstract

The invention discloses a motor position and rotating speed obtaining device and method, a chip and electrical equipment, the motor position and rotating speed obtaining device is applied to an inverter, the inverter comprises multiple phases of bridge arms, each phase of bridge arm comprises an upper bridge arm and a lower bridge arm, the upper bridge arm comprises an upper bridge arm switch tube connected with a fly-wheel diode in parallel, and the lower bridge arm comprises a lower bridge arm switch tube connected with a fly-wheel diode in parallel. The lower bridge arm comprises a lower bridge arm switching tube connected with a fly-wheel diode in parallel, and the device comprises a capturing module used for capturing the rising edge of the dead-zone voltage of the target bridge arm to obtain a first capturing signal and the falling edge of the dead-zone voltage to obtain a second capturing signal in the dead-zone time of the inverter, the target bridge arm is a bridge arm in which an upper bridge arm switch tube and a lower bridge arm switch tube are disconnected within the dead zone time, and the dead zone voltage is a voltage generated on the corresponding bridge arm by a current flowing through a fly-wheel diode within the dead zone time; and the control module is used for determining the motor rotor position and the motor rotating speed based on the first capture signal and the second capture signal.

Description

Technical Field

[0001] The present application relates to the field of motor control technology, and in particular to a device, method, chip and electrical equipment for obtaining motor position and speed. Background Art

[0002] Sensor control uses sensors to monitor and feedback the motor's motion state in real time, and then adjusts the motor's speed and position by controlling the motor's current size and direction. Sensors can usually measure parameters such as motor rotor position, speed, and acceleration. Common sensors include Hall sensors, encoders, and displacement sensors. Sensor control is widely used in situations that require high precision and high reliability, such as medical equipment, robots, and industrial automation. At the same time, sensor control can also be applied to speed regulation, positioning, tracking, and other occasions. Sensor control can be implemented in both hardware and software. The hardware method usually uses a dedicated position sensor, which increases the cost of motor control; the software method usually uses a synovial observer or a Lomborg sensorless observer, but the synovial observer and the Lomborg sensorless observer need to measure the relevant parameters of the motor, and the calculation is relatively complex, resulting in an increase in the computing power of the motor control chip. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first purpose of the present invention is to propose a motor position and speed acquisition device, which can obtain the capture signals of the two zero-crossing points of the target bridge arm phase current by capturing the first capture signal of the rising edge of the dead-zone voltage and the second capture signal of the falling edge of the dead-zone voltage within the dead-zone time of the target bridge arm. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the sensor control method in the related art, the control logic is simple, the computing power of the motor control chip will not be increased, and no position sensor is required, which reduces the cost of motor control.

[0004] The second objective of the present invention is to provide a chip.

[0005] The third object of the present invention is to provide an electrical device.

[0006] A fourth object of the present invention is to provide a method for acquiring the position and speed of a motor.

[0007] A fifth object of the present invention is to provide a computer-readable storage medium.

[0008] To achieve the above-mentioned purpose, according to an embodiment of the first aspect of the present invention, a motor position and speed acquisition device is proposed, which is applied to an inverter, and the inverter includes a multi-phase bridge arm, each phase bridge arm includes an upper bridge arm and a lower bridge arm, the upper bridge arm includes an upper bridge arm switch tube connected in parallel with a freewheeling diode, and the lower bridge arm includes a lower bridge arm switch tube connected in parallel with a freewheeling diode. The device includes: a capture module, which is used to capture the rising edge of the dead zone voltage of the target bridge arm within the dead zone time of the inverter to obtain a first capture signal and the falling edge of the dead zone voltage to obtain a second capture signal, wherein the target bridge arm is a bridge arm in which the upper bridge arm switch tube and the lower bridge arm switch tube are both disconnected within the dead zone time, and the dead zone voltage is the voltage generated on the corresponding bridge arm by the current flowing through the freewheeling diode within the dead zone time; a control module, which is used to determine the motor rotor position and the motor speed based on the first capture signal and the second capture signal.

[0009] According to the motor position and speed acquisition device of the embodiment of the present invention, it includes a capture module and a control module. The capture module captures the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage within the dead zone time of the target bridge arm. The rising edge of the dead zone voltage and the falling edge of the dead zone voltage correspond to the two zero-crossing points of the phase current of the target bridge arm. The capture module can obtain the capture signals of the two zero-crossing points. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the software method in the related art, the motor position and speed acquisition device of this embodiment has simple control logic, high reliability, and is not prone to errors, and does not need to measure the relevant parameters of the motor, such as inductance, resistance and flux linkage parameters. In addition, the motor parameter acquisition device does not require complex trigonometric function operations and floating-point data, so the computing power of the motor control chip can be reduced. Compared with the hardware method in the related art, the motor position and speed acquisition device of this embodiment does not require position sensors such as Hall sensors and magnetic encoders, thereby reducing the cost of motor control.

[0010] According to one embodiment of the present invention, the capture module includes a capturer arranged at each phase bridge arm of the corresponding inverter, and the capturer is used to capture the rising edge of the dead zone voltage when the corresponding phase bridge arm is used as the target bridge arm to obtain a first capture signal and the falling edge of the dead zone voltage to obtain a second capture signal within the dead zone time.

[0011] According to an embodiment of the present invention, the capture device obtains the dead zone voltage when the corresponding bridge arm is used as the target bridge arm within the dead zone time through a single-ended voltage sampling circuit.

[0012] According to an embodiment of the present invention, the first capture signal and the second capture signal are count values ​​of a counter, and the control module is specifically configured to determine the motor speed according to a signal difference between the second capture signal and the first capture signal.

[0013] According to one embodiment of the present invention, the first capture signal and the second capture signal are interrupt signals, and the control module is also used to obtain a first interrupt time when the first capture signal is received and a second interrupt time when the second capture signal is received, and determine the motor speed based on the time difference between the second interrupt time and the first interrupt time.

[0014] According to one embodiment of the present invention, the control module is further configured to determine the motor rotor position based on the first captured signal and the second captured signal.

[0015] According to an embodiment of the present invention, the control module is further configured to perform interpolation processing on the motor rotor position to obtain the interpolated motor rotor position.

[0016] According to an embodiment of the present invention, the control module is further configured to perform open-loop control on the motor using a constant voltage-frequency ratio or a constant current-frequency ratio.

[0017] To achieve the above objective, a chip is provided according to a second aspect of the present invention, comprising a motor position and speed acquisition device according to any of the above embodiments.

[0018] According to the chip of the embodiment of the present invention, by adopting the above-mentioned motor position and speed acquisition device, by capturing the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage within the dead zone time of the target bridge arm, the capture signals of the two zero-crossing points of the target bridge arm phase current can be obtained. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the sensor control method in the related art, the control logic is simple, the computing power of the motor control chip will not be increased, and no position sensor is required, thereby reducing the cost of motor control.

[0019] To achieve the above-mentioned purpose, an electrical device is proposed according to a third aspect of the present invention, comprising the motor position and speed acquisition device of any of the aforementioned embodiments, or the aforementioned chip.

[0020] According to the electrical equipment of an embodiment of the present invention, by adopting the above-mentioned motor position and speed acquisition device or chip, by capturing the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage within the dead zone time of the target bridge arm, the capture signals of the two zero-crossing points of the target bridge arm phase current can be obtained. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the sensor control method in the related art, the control logic is simple, the computing power of the motor control chip will not be increased, and no position sensor is required, thereby reducing the cost of motor control.

[0021] To achieve the above-mentioned purpose, according to an embodiment of the fourth aspect of the present invention, a method for obtaining the position and speed of a motor is proposed, which is applied to an inverter. The inverter includes a multi-phase bridge arm, each phase bridge arm includes an upper bridge arm and a lower bridge arm, the upper bridge arm includes an upper bridge arm switch tube connected in parallel with a freewheeling diode, and the lower bridge arm includes a lower bridge arm switch tube connected in parallel with a freewheeling diode. The method includes: within the dead time of the inverter, capturing the rising edge of the dead zone voltage of the target bridge arm to obtain a first capture signal and the falling edge of the dead zone voltage to obtain a second capture signal, wherein the target bridge arm is a bridge arm in which the upper bridge arm switch tube and the lower bridge arm switch tube are both disconnected during the dead time, and the dead zone voltage is the voltage generated on the corresponding bridge arm by the current flowing through the freewheeling diode during the dead time; based on the first capture signal and the second capture signal, determining the motor rotor position and the motor speed.

[0022] According to the motor position and speed acquisition method of the embodiment of the present invention, by capturing the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage within the dead zone time of the target bridge arm, the rising edge of the dead zone voltage and the falling edge of the dead zone voltage correspond to the two zero-crossing points of the phase current of the target bridge arm, and the capture signals of the two zero-crossing points of the phase current of the target bridge arm can be obtained. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the software method in the related art, the motor position and speed acquisition method of this embodiment has simple control logic, high reliability, and is not prone to errors, and does not need to measure the relevant parameters of the motor, such as inductance, resistance, and flux linkage parameters. In addition, the motor position and speed acquisition method does not require complex trigonometric function operations and floating-point data, so the computing power of the motor control chip can be reduced. Compared with the hardware method in the related art, the motor position and speed acquisition method of this embodiment does not require position sensors such as Hall sensors and magnetic encoders, thereby reducing the cost of motor control.

[0023] To achieve the above-mentioned purpose, according to a fifth aspect of the present invention, a computer-readable storage medium is provided, on which a program is stored, and when the program is executed by a processor, the above-mentioned method for obtaining the motor position and speed is implemented.

[0024] According to the computer-readable storage medium of an embodiment of the present invention, by executing a computer program of the above-mentioned motor position and speed acquisition method, by capturing the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage within the dead zone time of the target bridge arm, the capture signals of the two zero-crossing points of the target bridge arm phase current can be obtained. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the sensor control method in the related art, the control logic is simple, the computing power of the motor control chip will not be increased, and a position sensor is not required, thereby reducing the cost of motor control.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a structural schematic diagram of an inverter according to an embodiment of the present invention;

[0027] Figure 2 is a schematic structural diagram of a device for acquiring motor position and speed according to an embodiment of the present invention;

[0028] Figure 3 is a control timing diagram of a target bridge arm according to an embodiment of the present invention;

[0029] Figure 4-5 A schematic diagram of the phase current direction of a target bridge arm according to some embodiments of the present invention;

[0030] Figure 6 is a schematic diagram of the structure of a capture module according to an embodiment of the present invention;

[0031] Figure 7 A schematic diagram of a dead zone phase voltage and a phase current of an inverter according to an embodiment of the present invention;

[0032] Figure 8 is a schematic structural diagram of a chip according to an embodiment of the present invention;

[0033] Figure 9-10 A schematic diagram of the structure of an electrical device according to an embodiment of the present invention;

[0034] Fig.11 The figure is a flow chart of a method for acquiring the position and speed of a motor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0036] The following describes the motor position and speed acquisition device, method, chip, electrical equipment and storage medium according to the embodiments of the present invention with reference to the accompanying drawings.

[0037] It should be noted that the motor position and speed acquisition device of the embodiment of the present invention can be applied to Figure 1 In the inverter shown, reference Figure 1As shown, the inverter 100 includes a three-phase bridge arm, which is respectively a U-phase bridge arm, a W-phase bridge arm and a V-phase bridge arm, so as to be connected to the U-phase, W-phase and V-phase of the motor M. Each phase bridge arm includes an upper bridge arm and a lower bridge arm, and the upper bridge arm of the three-phase bridge arm is connected to the preset bus power supply VBUS, and the lower bridge arm of the three-phase bridge arm is grounded GND. The upper bridge arm also includes an upper bridge arm switch tube QU connected in parallel with a freewheeling diode, and the lower bridge arm also includes a lower bridge arm switch tube QD connected in parallel with a freewheeling diode. By controlling the on-off of the six switch tubes in the three-phase bridge arm, the inverter can convert the DC power provided by the preset bus power supply VBUS into three-phase AC power, and then control the rotation of the motor. The control logic can be a variety of control logics such as two-by-two conduction and three-by-three conduction. The specific control logic is not expanded here.

[0038] It should be noted that the motor phase current sampling method of the embodiment of the present invention can be applied to an inverter with multiple phase bridge arms. Figure 1 The inverter of the three-phase bridge arm shown is exemplary and is not intended to limit the present application.

[0039] Figure 2 Schematic diagram of the structure of a device for acquiring motor position and speed according to an embodiment of the present invention. Figure 2 As shown, the motor position and speed acquisition device includes: a capture module 10 and a control module 20 .

[0040] Among them, the capture module 10 is used to capture the rising edge of the dead zone voltage of the target bridge arm within the dead zone time of the inverter to obtain a first capture signal and the falling edge of the dead zone voltage to obtain a second capture signal, wherein the target bridge arm is a bridge arm in which the upper bridge arm switch tube and the lower bridge arm switch tube are both disconnected during the dead zone time, and the dead zone voltage is the voltage generated on the corresponding bridge arm by the current flowing through the freewheeling diode during the dead zone time; the control module 20 is used to determine the motor rotor position and the motor speed based on the first capture signal and the second capture signal.

[0041] Specifically, the target bridge arm can be any phase of the three-phase bridge arm of the inverter. The dead time of the target bridge arm refers to the time when the upper bridge switch tube and the lower bridge switch tube of the target bridge arm need to be switched on in the control process of the inverter. Figure 3 As shown, in order to avoid the upper and lower bridge arms being turned on at the same time and causing damage to the inverter, the dead time is artificially set, such as Figure 3The t0-t1 period and the t2-t3 period shown in FIG. During the dead time, due to the presence of the freewheeling diodes in the upper bridge arm switch tube and the lower bridge arm switch tube of the target bridge arm, even if the upper bridge arm switch tube and the lower bridge arm switch tube are both turned off at this time, there is still a freewheeling circuit in the target bridge arm, so the target bridge arm will generate a dead voltage during the dead time. When the dead voltage of the target bridge arm switches between a high level and a low level, it means that the bridge arm switch tube of the phase bridge arm is switched, so that the motor is switched, and the rising and falling edges of the dead voltage correspond to the switching moment. At this time, the phase current of the target bridge arm is 0, so the rising and falling edges of the dead voltage correspond to the rising and falling edges of the dead voltage corresponding to the zero crossing point of the phase current. In motor control, the motor rotor position corresponding to the zero crossing point of the phase current of the three-phase bridge arm is determined. Therefore, the motor rotor position can be obtained based on the first capture signal and the second capture signal, and the motor speed can be obtained based on the motor rotor position.

[0042] Compared with the traditional method of using a sliding film observer or a Lomborg sensorless observer to obtain the motor rotor position, the motor parameter acquisition device of the embodiment of the present invention does not need to measure the inductance and resistance of the motor and the flux parameters, and can reduce the computing power requirements of the MCU, does not require complex arctan, sin and cos operations, does not require floating point data, and has low requirements for chips. Therefore, it has the advantages of simple control logic, high reliability and low error. Compared with the solution of using sensors (such as Hall sensors, magnetic encoders) to obtain the motor rotor position in the related art, the motor position and speed acquisition device of the embodiment of the present invention has the advantage of low cost.

[0043] It should be noted that since the motor position and speed acquisition device of the embodiment of the present invention only works within the dead time of the inverter, the corresponding sampling frequency can be set based on the dead time of the inverter. For example, when the inverter is controlled in a three-three conduction mode, each phase bridge arm performs two phase changes in a single control cycle. Therefore, the sampling frequency can be set to twice the control frequency. For example, when the control frequency of the inverter is 16KHZ, the sampling frequency of the current sampling method of the embodiment of the present invention can be 32KHZ, which can achieve the effect of determining the phase current size and direction of the motor and determining the corresponding rotor position within the dead time.

[0044] Furthermore, since each phase bridge arm has two zero crossing points in one electrical cycle, when the inverter is Figure 1 When the three-phase bridge arm is shown, the inverter has a total of 6 zero crossing points. Therefore, the inverter can capture 6 times in one electrical cycle. Each time a capture occurs, the rotor speed can be updated once, so that the rotor position and rotor speed can be updated 6 times in one electrical cycle.

[0045] For example, if Figure 4As shown, when there is a freewheeling current in the freewheeling diode in the upper bridge arm of the U-phase bridge arm, the freewheeling current is a forward current, and the dead zone voltage is VBUS+Vd, where VBUS is the DC bus voltage, which can be obtained through real-time detection, and Vd is the conduction voltage of the freewheeling diode, which can be obtained by obtaining the diode parameters. Figure 5 As shown, when there is a freewheeling current in the freewheeling diode in the lower bridge arm of the U-phase bridge arm, the freewheeling current is a negative current and the dead zone voltage is 0-Vd.

[0046] It should be noted that when the target bridge arm is the V phase or the W phase, the method for obtaining the dead zone voltage is similar to the method for obtaining the dead zone voltage of the U phase bridge arm, which will not be described in detail here.

[0047] In the above embodiment, by capturing the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage, the capture signals of the two zero-crossing points of the target bridge arm phase current can be obtained. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the sensor control method in the related art, the control logic is simple, the computing power of the motor control chip will not be increased, and no position sensor is required, which reduces the cost of motor control. In addition, since the motor position and speed acquisition device only works within the dead zone time, it will not be interfered by the phase voltage, so that the motor speed and motor rotor position are more accurate.

[0048] In some embodiments, Figure 6 As shown, the capture module 10 includes a capture device 11-13 set for each phase bridge arm of the corresponding inverter. The capture device 11-13 is used to capture the rising edge of the dead zone voltage when the corresponding phase bridge arm is used as the target bridge arm during the dead zone time to obtain a first capture signal and the falling edge of the dead zone voltage to obtain a second capture signal.

[0049] Take the three-phase bridge arm inverter as an example. Figure 6 As shown, the dead zone voltage of the U-phase bridge arm is input to the first capturer 11, the dead zone voltage of the V-phase bridge arm is input to the second capturer 12, and the dead zone voltage of the W-phase bridge arm is input to the third capturer 13. The first capturer 11 performs the first capture when the rising edge of the U-phase dead zone voltage is detected, and performs the second capture when the falling edge of the U-phase dead zone voltage is detected. The second capturer 12 performs the first capture when the rising edge of the V-phase dead zone voltage is detected, and performs the second capture when the falling edge of the V-phase dead zone voltage is detected. The third capturer 13 performs the first capture when the rising edge of the W-phase dead zone voltage is detected, and performs the second capture when the falling edge of the W-phase dead zone voltage is detected.

[0050] In some embodiments, Figure 2As shown, the capturers 11 - 13 obtain the dead zone voltage when the corresponding bridge arm is used as the target bridge arm within the dead zone time through the single-ended voltage sampling circuit 200 .

[0051] Specifically, a single-ended sampling circuit 200 can be set at the connection point between the upper bridge arm and the lower bridge arm in the three-phase bridge arm of the inverter. Taking the inverter of the three-phase bridge arm as an example, the single-ended sampling circuit 200 may include three identical single-ended sampling sub-circuits 210, and the sampling ends of the single-ended sampling sub-circuits 210 are respectively connected to the JU, JW, and JV nodes of the inverter 100, and the JU, JW, and JV nodes are the output ends of the corresponding phase AC of the inverter. Each single-ended voltage sampling sub-circuit 210 includes a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1, wherein one end of the first resistor R1 is connected to the JU, JW, or JV node, the other end of the first resistor R1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded, one end of the third resistor R3 is connected to one end of the second resistor R2, and the other end of the third resistor R3 is connected to the corresponding capture device, one end of the first capacitor C1 is connected to the other end of the third resistor R3, and the other end of the first capacitor C1 is grounded. The first resistor R1 and the second resistor R2 are used to divide the dead zone voltage, and the third resistor R3 and the first capacitor C1 are used to filter the divided dead zone voltage to filter out noise in the dead zone voltage, so as to make the dead zone voltage more accurate.

[0052] It should be noted that the single-ended voltage sampling circuit 200 operates in analog input mode when no capture is performed, and is used to detect the back electromotive force of the motor. When the motor control chip sends a PWM (Pulse Width Modulation) drive signal, the single-ended voltage sampling circuit 200 is switched to timer input capture mode, which is used to detect the rising and falling edges of the dead zone voltage.

[0053] In some embodiments, the first captured signal and the second captured signal are count values ​​of a counter, and the control module is specifically configured to determine the motor speed according to a signal difference between the second captured signal and the first captured signal.

[0054] Specifically, the count value of the counter is a value related to the rotation speed. The slower the rotation speed, the larger the count value. When the first capture is generated at the rising edge of the dead zone voltage, the first count value of the counter is latched into the capture register, and a capture interrupt request is generated at the same time. A capture is recorded in the capture interrupt service program, for example, by a flag variable, and then the first count value is read from the capture register. When the second capture is generated at the falling edge of the dead zone voltage, the second count value of the counter is latched into the capture register, and the capture interrupt is entered again. The second count value in the capture register is read in the capture interrupt, and the capture record flag is cleared. Therefore, the speed of the motor can be calculated based on the difference between the first count value and the second count value.

[0055] In some embodiments, the first capture signal and the second capture signal are interrupt signals, and the control module 20 is also used to obtain the first interrupt time when the first capture signal is received and the second interrupt time when the second capture signal is received, and determine the motor speed based on the time difference between the second interrupt time and the first interrupt time.

[0056] Specifically, when the first capture signal and the second capture signal are count values, the count values ​​need to be stored in the capture register first, and then read from the capture register, which increases the acquisition time of the capture signal, thereby increasing the determination time of the rotor speed, which in turn affects the control efficiency of the motor. Therefore, when the first capture signal and the second capture signal are interrupt signals, the motor speed can be directly calculated based on the first interrupt time of the first capture signal and the second interrupt time of the second capture signal, as well as the phase difference between the two interrupts, and the phase difference between the two interrupts can be determined based on the motor rotor position.

[0057] In the above embodiment, the motor speed is calculated directly according to the first interrupt time of the first capture signal and the second interrupt time of the second capture signal. There is no need to first store the count value in the capture register and then obtain the count value from the capture register, thereby shortening the time for determining the motor speed and further improving the control efficiency of the motor.

[0058] In some embodiments, the control module 20 is further configured to determine the motor rotor position based on the first captured signal and the second captured signal.

[0059] Specifically, Figure 7 As shown, Figure 7 Taking the U phase shown in the figure as an example, when the dead zone phase voltage of the U phase bridge arm switches between high level and low level, it means that the bridge arm switch tube of the phase bridge arm is switched, so that the motor is switched. During the switching, the phase current of the U phase bridge arm passes through the zero point. In the control logic of the motor, the motor rotor position corresponding to the zero point of the phase current of the three-phase bridge arm is determined. For example, refer to Figure 7As shown, six commutations are required in one control cycle of the inverter, one every 60°. At this time, the two zero crossings corresponding to the U-phase current are the second and fifth, respectively. The corresponding motor rotor positions should be 60° and 240°. Figure 7 It can be seen that the motor rotor position corresponding to the falling edge of the U-phase dead zone phase voltage is 60°, and the rotor position corresponding to the rising edge of the U-phase dead zone phase voltage is 240°, and the motor rotor positions of the remaining phases are similar. It can be seen that the motor rotor position corresponding to the rising and falling edges of the dead zone phase voltage of the U-phase bridge arm is determined.

[0060] In one control cycle of the motor, Figure 7 In the 0°~360° shown in the figure, the dead zone voltage of the U-phase bridge arm has undergone two high-low level switches, and the falling edge or rising edge of the switch is the dead zone time. During the dead zone time, when the dead zone phase voltage of the U-phase bridge arm switches from a high level to a low level, the freewheeling current in the motor U phase will be Figure 4 The direction shown becomes Figure 5 The direction shown is switched from positive to negative. Therefore, if the phase current direction of the U-phase bridge arm is detected to switch to the negative direction during actual operation, it means that the motor commutation time has arrived. Figure 7 The falling edge position of the U-phase dead zone phase voltage is shown in FIG. 1 ; similarly, when the phase current direction of the U-phase bridge arm is detected to switch from the negative direction to the positive direction during actual operation, it indicates that the motor commutation time has arrived. Figure 7 The rising edge position of the U-phase dead zone phase voltage is shown in FIG. 1 , and it can be seen from the above that the motor rotor position corresponding to the rising edge and falling edge of the dead zone phase voltage of the U-phase bridge arm is determined. Because the first capture signal is captured at the rising edge of the dead zone voltage, and the second capture signal is captured at the falling edge of the dead zone voltage, the rotor position can be determined based on the first capture signal and the second capture signal.

[0061] In some embodiments, the control module 20 is further configured to perform interpolation processing on the motor rotor position to obtain the interpolated motor rotor position.

[0062] It can be understood that by performing interpolation processing on the motor rotor position, the rotor positions corresponding to more time periods can be obtained, so that a more accurate rotor position can be obtained based on the first captured signal and the second captured signal.

[0063] In some embodiments, the control module 20 is further configured to perform open-loop control on the motor using a constant voltage-frequency ratio or a constant current-frequency ratio.

[0064] Specifically, the voltage output by the inverter is proportional to the frequency by adopting a constant voltage-frequency ratio or a constant current-frequency ratio. For example, the motor can be started in current open loop and position open loop by setting the motor angle at a constant speed, the direct axis voltage is 0, and the quadrature axis voltage is a preset value, so that the motor can run smoothly to the target speed. In this state, the voltage, current, and back electromotive force of the motor are in a balanced state, and the phase difference is constant.

[0065] In the above embodiment, the motor is open-loop controlled by adopting a constant voltage-frequency ratio or a constant current-frequency ratio so that the voltage output by the inverter is proportional to the frequency, thereby making the phase difference between the voltage, current and back electromotive force of the motor constant. Therefore, the rotor position can be obtained through the first capture signal and the second capture signal.

[0066] In summary, the motor position and speed acquisition device according to the embodiment of the present invention includes a capture module and a control module. The capture module captures the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage within the dead zone time of the target bridge arm. The rising edge of the dead zone voltage and the falling edge of the dead zone voltage correspond to the two zero-crossing points of the phase current of the target bridge arm. The capture module can obtain the capture signals of the two zero-crossing points. Compared with the software method in the related art, the motor position and speed acquisition device of this embodiment has simple control logic, high reliability, and is not prone to error, and does not need to measure the relevant parameters of the motor, such as inductance, resistance and flux linkage parameters. In addition, the motor position and speed acquisition device does not require complex trigonometric function calculations and floating-point data, so the computing power of the motor control chip can be reduced. Compared with the hardware method in the related art, the motor position and speed acquisition device of this embodiment does not require position sensors such as Hall sensors and magnetic encoders, thereby reducing the cost of motor control. In addition, since the motor position and speed acquisition device only works within the dead zone time, it will not be interfered by the phase voltage, so that the motor speed and motor rotor position are more accurate.

[0067] Corresponding to the above embodiment, the embodiment of the present invention further provides a chip. Figure 8 As shown, the chip 400 includes the motor position and speed acquisition device 300 of any of the aforementioned embodiments.

[0068] It should be noted that the embodiment of the present invention focuses on the internal design of the chip using the above-mentioned motor position and speed acquisition device, and does not focus on controlling the motor operation according to the motor position and speed acquisition device.

[0069] According to the chip of the embodiment of the present invention, by adopting the above-mentioned motor position and speed acquisition device, by capturing the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage within the dead zone time of the target bridge arm, the capture signals of the two zero-crossing points of the target bridge arm phase current can be obtained. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the sensor control method in the related art, the control logic is simple, the computing power of the motor control chip will not be increased, and no position sensor is required, thereby reducing the cost of motor control.

[0070] Corresponding to the above embodiment, the embodiment of the present invention further provides an electrical device. Fig. 9 and Fig.10 As shown, the electrical device 500 includes the motor position and speed acquisition device 300 of any of the aforementioned embodiments, or the aforementioned chip 400.

[0071] It should be noted that the electrical equipment in this embodiment may be household electrical equipment, vehicles, office equipment or industrial equipment, and no specific limitation is made here.

[0072] According to the electrical equipment of an embodiment of the present invention, by adopting the above-mentioned motor position and speed acquisition device or chip, by capturing the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage within the dead zone time of the target bridge arm, the capture signals of the two zero-crossing points of the target bridge arm phase current can be obtained. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the sensor control method in the related art, the control logic is simple, the computing power of the motor control chip will not be increased, and no position sensor is required, thereby reducing the cost of motor control.

[0073] Corresponding to the above embodiment, the embodiment of the present invention further provides a method for obtaining the position and speed of a motor. Figure 1 The inverter 100 shown in FIG. Figure 1 As shown, the inverter 100 includes multi-phase bridge arms (U, V, W), each phase bridge arm includes an upper bridge arm and a lower bridge arm, the upper bridge arm includes an upper bridge arm switch tube with a freewheeling diode in parallel, and the lower bridge arm includes a lower bridge arm switch tube with a freewheeling diode in parallel.

[0074] like Fig.11 As shown, the method for obtaining the motor position and speed includes:

[0075] S101, within the dead time of the inverter, the rising edge of the dead time voltage of the target bridge arm is captured to obtain a first capture signal and the falling edge of the dead time voltage is captured to obtain a second capture signal, wherein the target bridge arm is a bridge arm in which both the upper bridge arm switch tube and the lower bridge arm switch tube are disconnected within the dead time, and the dead time voltage is the voltage generated on the corresponding bridge arm by the current flowing through the freewheeling diode within the dead time.

[0076] S102, determining a motor rotor position and a motor speed based on the first captured signal and the second captured signal.

[0077] According to the motor position and speed acquisition method of the embodiment of the present invention, by capturing the first capture signal of the rising edge of the dead zone voltage and the second capture signal of the falling edge of the dead zone voltage within the dead zone time of the target bridge arm, the capture signals of the two zero-crossing points of the target bridge arm phase current can be obtained. Since the rotor position is determined at the moment of the zero-crossing point, the motor rotor position can be obtained, and the motor speed can be determined based on the rotor position and the capture signal. Compared with the software method in the related art, the motor position and speed acquisition method of this embodiment has simple control logic, high reliability, and is not prone to errors, and does not require measurement of motor related parameters, such as inductance, resistance, and flux linkage parameters. In addition, the motor position and speed acquisition method does not require complex trigonometric function calculations and floating-point data, so the computing power of the motor control chip can be reduced. Compared with the hardware method in the related art, the motor position and speed acquisition method of this embodiment does not require position sensors such as Hall sensors and magnetic encoders, thereby reducing the cost of motor control.

[0078] Corresponding to the above embodiment, an embodiment of the present invention further provides a computer-readable storage medium on which a program is stored. When the program is executed by a processor, the above-mentioned method for obtaining the motor position and speed is implemented.

[0079] According to the computer-readable storage medium of an embodiment of the present invention, by executing a computer program of the above-mentioned motor position and speed acquisition method, by capturing the first capture signal of the rising edge of the dead-zone voltage and the second capture signal of the falling edge of the dead-zone voltage within the dead-zone time of the target bridge arm, the capture signals of two zero-crossing points can be determined. Since there is a certain relationship between the phase difference of the current and the phase difference of the rotor within the dead-zone time, the motor speed and rotor position can be determined based on the first capture signal and the second capture signal. Compared with the sensor control method in the related art, the control logic is simple, the computing power of the motor control chip will not be increased, and a position sensor is not required, thereby reducing the cost of motor control.

[0080] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0081] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0083] In addition, the terms "first", "second", etc. used in the embodiments of the present invention are only used for descriptive purposes and should not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features indicated in the present embodiment. Therefore, the features defined by the terms "first", "second", etc. in the embodiments of the present invention can explicitly or implicitly indicate that the embodiment includes at least one of the features. In the description of the present invention, the word "multiple" means at least 2 or 2 and more, such as 2, three, four, etc., unless otherwise clearly and specifically defined in the embodiments.

[0084] In the present invention, unless otherwise clearly specified or limited in the embodiments, the terms "installed", "connected", "connected" and "fixed" etc. appearing in the embodiments should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integrated connection. It can be understood that it can also be a mechanical connection, an electrical connection, etc.; of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements, or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific implementation situation.

[0085] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A device for obtaining motor position and speed, characterized in that: Applied to an inverter, the inverter includes a multi-phase bridge arm, each phase bridge arm includes an upper bridge arm and a lower bridge arm, the upper bridge arm includes an upper bridge arm switch tube connected in parallel with a freewheeling diode, the lower bridge arm includes a lower bridge arm switch tube connected in parallel with a freewheeling diode, and the device includes: A capture module, used for capturing the rising edge of the dead-zone voltage of the target bridge arm within the dead-zone time of the inverter to obtain a first capture signal and the falling edge of the dead-zone voltage to obtain a second capture signal, wherein the target bridge arm is a bridge arm in which both the upper bridge arm switch tube and the lower bridge arm switch tube are disconnected within the dead-zone time, and the dead-zone voltage is the voltage generated on the corresponding bridge arm by the current flowing through the freewheeling diode within the dead-zone time; A control module is used to determine the motor rotor position and the motor speed based on the first captured signal and the second captured signal.

2. The device according to claim 1, characterized in that The capture module includes a capturer set corresponding to each phase bridge arm of the inverter, and the capturer is used to capture the rising edge of the dead zone voltage when the corresponding phase bridge arm is used as the target bridge arm during the dead zone time to obtain a first capture signal and the falling edge of the dead zone voltage to obtain a second capture signal.

3. The device according to claim 2, characterized in that The capture device acquires the dead zone voltage when the corresponding bridge arm is used as the target bridge arm within the dead zone time through a single-ended voltage sampling circuit.

4. The device according to any one of claims 1 to 3, characterized in that: The first captured signal and the second captured signal are count values ​​of a counter, and the control module is specifically configured to determine the motor speed according to a signal difference between the second captured signal and the first captured signal.

5. The device according to any one of claims 1 to 3, characterized in that: The first capture signal and the second capture signal are interrupt signals. The control module is also used to obtain a first interrupt time when the first capture signal is received and a second interrupt time when the second capture signal is received, and determine the motor speed according to the time difference between the second interrupt time and the first interrupt time.

6. The device according to claim 1, characterized in that The control module is further configured to determine a motor rotor position based on the first captured signal and the second captured signal.

7. The device according to claim 6, characterized in that The control module is also used to perform interpolation processing on the motor rotor position to obtain the interpolated motor rotor position.

8. The device according to claim 1, characterized in that The control module is also used to perform open-loop control on the motor using a constant voltage-frequency ratio or a constant current-frequency ratio.

9. A chip, characterized in that: It comprises the motor position and speed acquisition device according to any one of claims 1-8.

10. An electrical device, characterized in that: It comprises the motor position and speed acquisition device according to any one of claims 1 to 8, or the chip according to claim 9.

11. A method for obtaining motor position and speed, characterized in that: Applied to an inverter, the inverter includes a multi-phase bridge arm, each phase bridge arm includes an upper bridge arm and a lower bridge arm, the upper bridge arm includes an upper bridge arm switch tube connected in parallel with a freewheeling diode, the lower bridge arm includes a lower bridge arm switch tube connected in parallel with a freewheeling diode, and the method includes: During the dead time of the inverter, the rising edge of the dead time voltage of the target bridge arm is captured to obtain a first capture signal, and the falling edge of the dead time voltage is captured to obtain a second capture signal, wherein the target bridge arm is a bridge arm in which both the upper bridge arm switch tube and the lower bridge arm switch tube are disconnected during the dead time, and the dead time voltage is the voltage generated on the corresponding bridge arm by the current flowing through the freewheeling diode during the dead time; Based on the first captured signal and the second captured signal, a motor rotor position and a motor speed are determined.

12. A computer-readable storage medium, characterized in that: A program is stored thereon, and when the program is executed by a processor, the method for obtaining the motor position and speed according to claim 11 is implemented.

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