Motor rotor position acquisition device and method, chip and electrical equipment

Abstract

The invention discloses a motor rotor position obtaining device and method, a chip and electrical equipment, the 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 device comprises a comparison module used for comparing a dead-zone voltage of a target bridge arm with a reference voltage within a dead-zone time of an inverter and outputting a comparison result, the target bridge arm being 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 reference voltage being a reference voltage; the dead-zone voltage is the voltage generated on the corresponding bridge arm by the current flowing through the freewheeling diode in the dead-zone time; and the control module is used for determining the position of the motor rotor based on the comparison result. According to the device, a high-reliability motor rotor position acquisition function can be realized without a sensor, so that the control cost of the motor can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of chip design, and in particular to a device and method for obtaining the position of a motor rotor, a chip, and electrical equipment. Background Art

[0002] In chips involved in motor control, sensors (such as Hall sensors and magnetic encoders) are usually used to monitor and provide feedback on operating parameters such as the motor rotor position and motor phase current in real time, so as to control the motor current magnitude and direction, and then adjust the motor speed and position to achieve real-time control of the motor. In actual applications, due to the high cost of sensors, they are not widely used. Therefore, related technologies usually adopt the sliding film and Lomborg sensorless observer methods to obtain the motor rotor position. This method estimates the motor rotor position by measuring parameters such as the motor's inductance, resistance, and magnetic flux, thereby achieving the function of determining the motor rotor position.

[0003] The disadvantage of the above-mentioned related technologies is that the electronic rotor position determination method requires measuring multiple parameters such as the motor's magnetic flux, and requires complex arctan, sin, and cos operations on these parameters. Therefore, the algorithm is relatively complex and requires high chip computing power, resulting in the corresponding motor control cost still being high. Summary of the Invention

[0004] The present invention aims to solve, at least to a certain extent, one of the technical problems in the related art. To this end, a first object of the present invention is to provide a motor rotor position acquisition device. By using a comparison module to compare the dead-zone voltage of a target bridge arm with a reference voltage during the dead-zone time of an inverter, and outputting the comparison result, a control module is used to determine the motor rotor position based on the comparison result. This function achieves the function of acquiring the motor rotor position without the need for a sensor. At the same time, the rotor position determination logic is simple and does not require measurement of motor parameters such as inductance and flux linkage, thereby effectively reducing the control cost of the motor and improving the reliability of the motor rotor position acquisition function.

[0005] The second object of the present invention is to provide a chip.

[0006] The third object of the present invention is to provide an electrical device.

[0007] A fourth objective of the present invention is to provide a motor phase current sampling device.

[0008] A fifth object of the present invention is to provide a computer-readable storage medium.

[0009] To achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention proposes a motor rotor position acquisition device, 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 with a freewheeling diode in parallel, and the lower bridge arm includes a lower bridge arm switch tube with a freewheeling diode in parallel. The device includes: a comparison module, which is used to compare the dead zone voltage of the target bridge arm with the reference voltage within the dead zone time of the inverter and output the comparison result, wherein the target bridge arm is the 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; and a control module, which is used to determine the motor rotor position based on the comparison result.

[0010] According to the motor rotor position acquisition device of an embodiment of the present invention, a comparison module is used to compare the dead-zone voltage of the target bridge arm with the reference voltage within the dead-zone time of the inverter, and a comparison result is output. Then, the motor rotor position is determined based on the comparison result by a control module, thereby realizing the function of acquiring the motor rotor position without the need for a sensor. At the same time, the logic for determining the rotor position is simple, and there is no need to measure parameters such as the inductance and magnetic flux of the motor, thereby effectively reducing the control cost of the motor and improving the reliability of the function of acquiring the motor rotor position.

[0011] According to one embodiment of the present invention, the comparison module includes a comparator set for each phase bridge arm of the corresponding inverter, and the comparator is used to compare the dead zone voltage when the corresponding phase bridge arm is used as the target bridge arm with the reference voltage within the dead zone time, and output the comparison result.

[0012] According to one embodiment of the present invention, the comparator obtains the dead-zone voltage of the corresponding bridge arm as the target bridge arm within the dead-zone time through the single-ended voltage sampling circuit.

[0013] According to one embodiment of the present invention, the reference voltage is determined based on the DC bus voltage of the inverter and the voltage sampling ratio of the single-ended voltage sampling circuit.

[0014] According to one embodiment of the present invention, the control module is specifically used to determine the motor rotor position when the comparison result switches from a first result to a second result, or from a second result to a first result, wherein the first result is a result corresponding to a dead zone voltage being greater than a reference voltage, and the second result is a result corresponding to a dead zone voltage being less than a reference voltage.

[0015] According to an embodiment of the present invention, the control module is further configured to generate and output an interrupt signal when the motor rotor position is determined, so as to control the motor based on the interrupt signal.

[0016] According to an embodiment of the present invention, the control module is further configured to generate a position signal and store the position signal in a register when the position of the motor rotor is determined, so as to control the motor based on the position signal in the register.

[0017] According to one 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.

[0018] To achieve the above-mentioned purpose, a second embodiment of the present invention provides a chip including the aforementioned motor rotor position acquisition device.

[0019] According to the chip of the embodiment of the present invention, through the aforementioned motor rotor position acquisition device, the function of acquiring the motor rotor position can be realized when the motor is working without the need for a sensor. At the same time, the logic for determining the rotor position is simple, and there is no need to measure the motor's inductance, magnetic flux and other parameters, thereby effectively reducing the control cost of the motor and improving the reliability of the function of acquiring the motor rotor position.

[0020] To achieve the above-mentioned purpose, a third embodiment of the present invention provides an electrical device, including the aforementioned motor rotor position acquisition device, or the aforementioned chip.

[0021] According to the electrical equipment of the embodiment of the present invention, through the aforementioned motor rotor position acquisition device or the aforementioned chip, the function of acquiring the motor rotor position can be realized when the motor is working without the need for a sensor. At the same time, the logic for determining the rotor position is simple, and there is no need to measure the motor's inductance, magnetic flux and other parameters, thereby effectively reducing the control cost of the motor and improving the reliability of the function of acquiring the motor rotor position.

[0022] To achieve the above-mentioned purpose, the fourth embodiment of the present invention proposes a method for obtaining the position of a motor rotor, 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 with a freewheeling diode in parallel, and the lower bridge arm includes a lower bridge arm switch tube with a freewheeling diode in parallel. The method includes: within the dead time of the inverter, comparing the dead time voltage of the target bridge arm with the reference voltage, and outputting the comparison result, wherein the target bridge arm is the 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 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 comparison result, determining the position of the motor rotor.

[0023] According to the motor rotor position acquisition method of an embodiment of the present invention, the dead zone voltage of the target bridge arm is compared with the reference voltage within the dead zone time of the inverter, and the comparison result is output. The motor rotor position is then determined based on the comparison result, thereby realizing the function of acquiring the motor rotor position without the need for a sensor. At the same time, the rotor position determination logic is simple, and there is no need to measure the motor's inductance, magnetic flux and other parameters, thereby effectively reducing the motor control cost and improving the reliability of the motor rotor position acquisition function.

[0024] To achieve the above-mentioned purpose, a fifth embodiment of the present invention proposes a computer-readable storage medium having a program stored thereon, which implements the aforementioned method for obtaining the motor rotor position when executed by a processor.

[0025] According to the computer-readable storage medium of an embodiment of the present invention, through the aforementioned motor rotor position acquisition method, the function of acquiring the motor rotor position can be realized when the motor is working without the need for a sensor. At the same time, the logic for determining the rotor position is simple, and there is no need to measure parameters such as the motor's inductance and magnetic flux, thereby effectively reducing the control cost of the motor and improving the reliability of the function of acquiring the motor rotor position.

[0026] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a structural diagram of an inverter according to an embodiment of the present invention;

[0028] Figure 2 2 is a schematic structural diagram of a device for acquiring a motor rotor position according to an embodiment of the present invention;

[0029] Figure 3 is a control timing diagram of a target bridge arm according to one embodiment of the present invention;

[0030] Figure 4a-4b A schematic diagram of current direction of an inverter according to an embodiment of the present invention;

[0031] Figure 5 is a schematic structural diagram of a comparison module according to an embodiment of the present invention;

[0032] Figure 6 2 is a schematic structural diagram of a single-ended voltage sampling circuit according to an embodiment of the present invention;

[0033] Figure 7 is a schematic diagram of dead-zone voltage and phase current of an inverter according to one embodiment of the present invention;

[0034] Figure 8A waveform diagram of an interrupt signal according to an embodiment of the present invention;

[0035] Figure 9 is a schematic structural diagram of a chip according to an embodiment of the present invention;

[0036] Figure 10a-10b A schematic structural diagram of an electrical device according to an embodiment of the present invention;

[0037] Figure 11 Flowchart of a method for obtaining the motor rotor position according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following describes embodiments of the present invention in detail, 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 are not to be construed as limiting the present invention.

[0039] The following describes the motor rotor position acquisition device and method, chip, electrical equipment, and computer-readable storage medium proposed in the embodiments of the present invention with reference to the accompanying drawings.

[0040] It should be noted that the motor rotor position acquisition device of the embodiment of the present invention can be applied to Figure 1 In the inverter shown, refer to Figure 1 As shown, the inverter 100 includes three-phase bridge arms, namely the U-phase bridge arm, the W-phase bridge arm, and the V-phase bridge arm, which are 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 arms of the three-phase bridge arms are all connected to the DC bus power supply VBUS, and the lower bridge arms of the three-phase bridge arms are all grounded GND. The upper bridge arm also includes an upper bridge arm switch tube QU with a freewheeling diode in parallel, and the lower bridge arm also includes a lower bridge arm switch tube QD with a freewheeling diode in parallel. By controlling the on and off of the six switches in the three-phase bridge arm, the inverter 100 can convert the DC power provided by the DC bus power supply VBUS into three-phase AC power, thereby controlling the rotation of the motor M. 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.

[0041] Figure 2 FIG. 1 is a schematic diagram of a motor rotor position acquisition device according to an embodiment of the present invention, referring to FIG. Figure 2 As shown, the device 200 includes: a comparison module 210 and a control module 220.

[0042] Among them, the comparison module 210 is used to compare the dead zone voltage of the target bridge arm with the reference voltage during the dead zone time of the inverter 100, and output the comparison result, wherein the target bridge arm is the 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 220 is used to determine the motor rotor position based on the comparison result.

[0043] Specifically, in the control process of the inverter 100, in order to realize the phase commutation function of the motor M, a phase in the three-phase bridge arm needs to switch the upper bridge arm switch tube QU and the lower bridge arm switch tube QD. At this time, the phase bridge arm is the target bridge arm. In order to avoid the upper and lower bridge arm switches of the target bridge arm being turned on at the same time, which may cause damage to the inverter 100, it is necessary to set a period as a dead zone period before switching on, such as Figure 3 During the periods t0 to t1 and t2 to t3, both the upper-arm switch QU and the lower-arm switch QD in the phase bridge arm are turned off, and then the conduction switching function is performed to protect the inverter 100. From the above analysis, it can be seen that during the dead time of the inverter 100, the bridge arm in which both the upper-arm switch QU and the lower-arm switch QD are turned off is the target bridge arm.

[0044] After determining the target bridge arm of the current dead time, refer to Figure 1 As shown, taking the U-phase bridge arm as the target bridge arm as an example, during the dead time of the U-phase bridge arm, although the upper bridge arm switch tube QU and the lower bridge arm switch tube QD are both turned off, since these two switch tubes have freewheeling diodes, different freewheeling circuits will be generated in the U-phase bridge arm at this time according to the size of the phase voltage of the U-phase. The voltage generated on the upper bridge arm or the lower bridge arm by the current flowing through the freewheeling diode at this time can be obtained in a variety of ways. This voltage is the dead time voltage, where the reference Figure 4a As shown in FIG, when the current of the freewheeling circuit flows through the upper bridge arm, the current direction is from the U phase of the motor through the freewheeling diode of the upper bridge arm switch tube DU to the DC bus power supply VBUS. Therefore, the dead zone voltage at this time is higher than the DC bus voltage VBUS; or, refer to FIG. Figure 4b As shown, when the current of the freewheeling loop flows through the lower bridge arm, the current direction at this time is from the ground terminal GND through the freewheeling diode of the lower bridge arm switch tube QD to the U phase of the motor, and the dead zone voltage at this time is lower than zero. It can be seen that during the dead zone time, according to the phase voltage size of the corresponding phase of the target bridge arm, different freewheeling loops are generated in the target bridge arm. At this time, the dead zone voltage detected will jump between positive and negative values. Therefore, the comparison module 210 can compare the acquired dead zone voltage with the preset reference voltage and output the comparison result. Then the control module 220 can determine whether the freewheeling loop in the inverter at this time is positive or negative based on the comparison result. Figure 4a and Figure 4b One of the freewheeling circuits shown is used to determine the commutation moment of the motor M at this time. In the control logic of the motor M, the motor rotor position corresponding to the fixed commutation moment is also fixed. Therefore, the control module 220 can determine the corresponding motor rotor position based on the comparison result.

[0045] As can be seen from the above, the acquisition device 200 of the embodiment of the present invention can determine the rotor position of the motor M by detecting the dead-zone voltage of the target bridge arm in the inverter 100. Compared with the method of using sliding film and Lomborg sensorless observer to determine the motor rotor position in the related art, the acquisition device 200 of the embodiment of the present invention only involves the dead-zone voltage as a measurement parameter, and does not need to measure the inductance, resistance and flux parameters of the motor M; at the same time, the logic of the acquisition process of the acquisition device 100 for the motor rotor position is relatively simple, and neither complex arctan, sin and cos operations nor floating-point data are required. Therefore, the acquisition device 200 has low requirements for chip computing power and performance, and the error probability is also low. As a result, the acquisition device of the embodiment of the present invention has the advantages of simple logic, high reliability and not prone to errors. In addition, compared with the method of using sensors to obtain the motor rotor position, the acquisition device of the embodiment of the present invention also has the advantage of low cost.

[0046] In the above embodiment, by using a comparison module to compare the dead-zone voltage of the target bridge arm with the reference voltage within the dead-zone time of the inverter and outputting the comparison result, the motor rotor position is determined based on the comparison result by the control module, thereby realizing the function of obtaining the motor rotor position without the need for a sensor. At the same time, the logic for determining the rotor position is simple, and there is no need to measure parameters such as the inductance and magnetic flux of the motor, thereby effectively reducing the control cost of the motor and improving the reliability of the function of obtaining the motor rotor position.

[0047] In some embodiments, reference Figure 5 As shown, the comparison module 210 includes a comparator COMP set corresponding to each phase bridge arm of the inverter 100. The comparator COMP is used to compare the dead zone voltage when the corresponding phase bridge arm is used as the target bridge arm with the reference voltage within the dead zone time and output the comparison result.

[0048] Furthermore, the comparator COMP obtains 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 300 .

[0049] Specifically, in the control cycle of the motor M, each of the three-phase bridge arms will serve as the target bridge arm at a certain commutation moment. Therefore, a single-ended voltage sampling circuit 300 can be provided at the output end of the three-phase AC power of the inverter 100. This circuit can collect the dead zone voltage of the target bridge arm when the corresponding bridge arm serves as the target bridge arm, and transmit it to the corresponding comparator COMP in the comparison module 210. For example, referring to Figure 5 As shown, the comparison module 210 includes three comparators COMP1 to COMP3, which compare the dead zone voltages when the U, V, and W phases are used as target bridge arms. The following uses the comparator COMP1 corresponding to U as an example to illustrate the working mode of the comparator. Figure 5 As shown, the first input terminal of the comparator COMP1 is connected to the U-phase bridge arm voltage collection point Vbemf_U of the single-ended voltage sampling circuit 300, the second input terminal of the comparator COMP1 is connected to the reference voltage terminal VREF, and the output terminal of the comparator COMP1 is connected to the control module 220. When the single-ended voltage sampling circuit 300 collects the dead-zone voltage of the target bridge arm, the comparator COMP1 can obtain the collected dead-zone voltage from the first input terminal, compare the dead-zone voltage with the reference voltage provided by the reference voltage terminal VREF, obtain a comparison result, and output it to the control module 220. In this way, the comparison module realizes the function of comparing the dead-zone voltage with the reference voltage and outputting the comparison result.

[0050] Optionally, the single-ended voltage sampling circuit 300 may be as follows: Figure 6 As shown, reference Figure 6As shown, the single-ended voltage sampling circuit 300 may include three identical single-ended sampling sub-circuits 310. The three sampling terminals of the single-ended sampling sub-circuit 310 are respectively connected to the JU, JW, and JV nodes of the inverter 100, where the JU, JW, and JV nodes are the output terminals of the corresponding phase AC power of the inverter 100, and the three sampling points (Vbemf_U, Vbemf_V, Vbemf_W) of the single-ended sampling sub-circuit 310 are respectively connected to the corresponding comparators (COMP1, COMP2, COMP3). The three single-ended sampling sub-circuits 310 have the same circuit structure. Taking the single-ended sampling sub-circuit 310 of the U-phase bridge arm as an example, the circuit 310 includes first to third resistors R1-R3 and a capacitor C. One end of the first resistor R1 is grounded to GND, and the other end of the first resistor R1 is connected to one end of the second resistor R2 and one end of the third resistor R3, respectively. The other end of the second resistor R2 is connected to the node JU as a sampling end. The other end of the third resistor R3 is connected to one end of the capacitor C and serves as the voltage sampling point Vbemf_U of the single-ended voltage sampling circuit 300. The other end of the capacitor C is grounded to GND. The circuit primarily collects the voltage of the upper or lower bridge arm of the U-phase bridge arm as the dead-zone voltage based on the voltage divider principle between the first resistor R1 and the second resistor R2. At the same time, the capacitor C has a voltage stabilizing function, and the third resistor R3 has a current limiting function to prevent excessive current in the single-ended voltage sampling circuit 300.

[0051] When the single-ended voltage sampling circuit 300 is as Figure 6 As shown, the process of obtaining the dead zone voltage of the target bridge arm of the inverter 100 is as follows: When the U-phase bridge arm is the target bridge arm, there are two situations in the freewheeling circuit on the U-phase bridge arm according to the level of the U-phase phase voltage of the motor M. In the first situation, the U-phase phase voltage is high and there is current in the upper bridge arm of the U-phase bridge arm. At this time, the current path in the inverter 100 is as follows: Figure 4a As shown, one current path starts from the JU node, passes through the second resistor R2 and the first resistor R1 to the ground terminal GND, and the other current path starts from the JU node, passes through the second resistor R2 and the third resistor R3 to the comparison module 210. At this time, according to the voltage division principle, the following formula (1) can be obtained:

[0052] Vbemf_U=VU*R1 / (R2+R2) (1)

[0053] Wherein, Vbemf_U is the sampled voltage collected by the single-ended voltage sampling circuit 300, VU is the voltage generated in the upper bridge arm by the current flowing through the freewheeling diode, that is, the dead zone voltage, R1 is the resistance value of the first resistor R1, and R2 is the resistance value of the second resistor R2. Therefore, the dead zone voltage VU of the U-phase bridge arm at this time can be obtained by the above formula (1).

[0054] Alternatively, in the second case, the U-phase voltage is low and there is current in the lower arm of the U-phase bridge arm. At this time, the current path in the inverter is as follows: Figure 4b As shown, one current path starts from the ground terminal GND, passes through the first resistor R1 and the second resistor R2 to the JU node, and the other current path starts from the ground terminal GND, passes through the first resistor R1 and the third resistor R3 to the comparison module 210. At this time, the dead zone voltage VU can also be obtained according to the above formula (1).

[0055] Optionally, since the acquisition device 200 of the embodiment of the present invention only operates within the dead time of the inverter 100, the above-mentioned single-ended voltage sampling circuit 300, in addition to realizing the aforementioned function of detecting the target bridge arm dead time voltage, can also be used to detect the back electromotive force of the motor M to realize the forward and backward wind detection of the motor. The two do not conflict. Therefore, in actual operation, the single-ended voltage sampling circuit 300 can first operate in the analog input mode to detect the back electromotive force for forward and backward wind detection; then, when the acquisition device 200 determines that the motor enters the dead time, the single-ended voltage sampling circuit 300 can switch to the comparison mode to input the collected dead time voltage to the comparison module 210, so that the acquisition device 200 can operate normally. This realizes the reuse of the single-ended voltage sampling circuit, thereby further reducing the control cost of the motor.

[0056] It should be noted that the motor rotor position acquisition device according to the embodiment of the present invention may also adopt other types of single-ended voltage sampling circuits 300. Figure 6 The single-ended voltage sampling circuit 300 shown is exemplary and is not intended to limit the present application.

[0057] In some embodiments, the reference voltage is determined based on the DC bus voltage of the inverter 100 and the voltage sampling ratio of the single-ended voltage sampling circuit 300 .

[0058] Specifically, the reference voltage is mainly used to compare with the dead zone voltage of the target bridge arm to determine whether the freewheeling circuit is Figure 4a or Figure 4b In one of the two freewheeling circuits, the theoretical dead zone voltage is calculated as follows: When the freewheeling circuit in the inverter 100 is as follows Figure 4a As shown, at this time, according to the voltage division principle, the following formula (2) can be obtained:

[0059] VU=VBUS+Vd (2)

[0060] Among them, VU is the dead zone voltage at this time, which can be Figure 6 The single-ended voltage sampling circuit 300 shown is obtained, VBUS is the DC bus voltage of the inverter 100, which can be obtained through real-time detection; Vd is the diode conduction voltage, which can be obtained by obtaining diode parameters.

[0061] When the freewheeling circuit in the inverter 100 is Figure 4b As shown, at this time, according to the voltage division principle, the following formula (3) can be obtained:

[0062] VU=0-Vd (3)

[0063] Among them, VU is the upper arm voltage, which can be Figure 6 The single-ended voltage sampling circuit 300 shown is obtained; Vd is the diode conduction voltage, which can be obtained by obtaining the diode parameters.

[0064] It can be seen from this that the dead zone voltage of the target bridge arm should fluctuate between -Vd and VBUS+Vd, where the conduction voltage of the diode is small and can be ignored. Therefore, in theory, the reference voltage can be selected as any value between zero and the DC bus voltage VBUS, which can enable the comparison module 210 to work normally.

[0065] Meanwhile, the voltage sampling ratio of the single-ended voltage sampling circuit 300 refers to the multiple by which the single-ended voltage sampling circuit 300 reduces or amplifies the actual dead zone voltage during the sampling process. For example, Figure 6 In the single-ended voltage sampling circuit 300 shown, the voltage sampling ratio is the ratio of the first resistor R1 to the second resistor R2. Therefore, the reference voltage used as the comparison object also needs to be multiplied by the same magnification or reduction factor to ensure that the comparison module 210 can work properly.

[0066] Preferably, the middle value between zero and the DC bus voltage VBUS can be selected as the reference voltage. Assuming that the voltage sampling ratio of the single-ended voltage sampling circuit 300 is S, the reference voltage can be VBUS / 2 / S, so that the comparison module 210 obtains the best comparison effect.

[0067] Furthermore, the control module 210 is specifically used to determine the motor rotor position when the comparison result switches from a first result to a second result, or from a second result to a first result, wherein the first result is the result corresponding to the dead zone voltage being greater than the reference voltage, and the second result is the result corresponding to the dead zone voltage being less than the reference voltage.

[0068] Specifically, it can be seen from the above that within the dead zone time, the dead zone voltage of the target bridge arm will only jump between the two voltage values ​​of -Vd and VBUS+Vd (hereinafter referred to as low level and high level respectively). When the dead zone voltage of the target bridge arm is a high level, the dead zone voltage is greater than the reference voltage, and the comparison module 210 outputs the first result. When the dead zone voltage of the target bridge arm is a low level, the dead zone voltage is less than the reference voltage, and the comparison module 210 outputs the second result.

[0069] Subsequently, after the voltage value of the dead zone voltage is determined, the jump curve of the dead zone voltage can be determined in combination with the control logic of the motor M. For example, when the motor is controlled in a three-three conduction manner, the three-phase current of the motor M and the resulting dead zone voltage can be as follows: Figure 7 As shown, Figure 7 Taking the U-phase bridge arm shown in the figure as an example, when the dead zone voltage of the U-phase bridge arm switches between high and low levels, it means that the upper and lower bridge arm switches of the phase bridge arm are switched, so that the motor M is commutated. In one control cycle, that is, Figure 7 In the range of 0° to 360° shown in the figure, the U-phase bridge arm undergoes two high-low level switches, and the falling or rising edge of the switch is the dead time. During the dead time, the U-phase current passes through the zero point, and in different motor control logics, the motor rotor position corresponding to the zero point is fixed. Figure 7 As shown, the U-phase current passes through the zero point twice. In a single control cycle of the motor, each phase needs to undergo two commutations, a total of six commutations, that is, one commutation every 60°. Figure 7 As shown, the two zero crossing points of the U-phase current are the second and fifth, respectively, and the corresponding motor rotor positions should be 60° and 240°. Among them, the falling edge of the U-phase dead zone voltage corresponds to the motor rotor position of 60°, and the rising edge of the U-phase dead zone voltage corresponds to the motor rotor position of 240°. The motor rotor positions of the remaining phases are similar. Therefore, after the comparison module 210 determines that the dead zone voltage of the U-phase bridge arm within the dead zone time is the rising edge and the falling edge, the motor rotor position at that time can be determined.

[0070] refer to Figure 7 As shown in the figure, during the dead time, when the dead phase voltage of the U phase bridge arm switches from high level to low level, the freewheeling current in the motor U phase will be Figure 4a The direction shown becomes Figure 4b As shown in the direction, the output result of the corresponding comparison module 220 also changes from the first result to the second result. Therefore, in actual operation, when the comparison control module 220 detects that the output result of the comparison module 210 changes from the first result to the second result, it means that the commutation time of the motor M has arrived. Figure 7 The falling edge position of the U-phase dead zone voltage shown in FIG. 1 can determine that the motor rotor position at this time is 60°; similarly, if the control module 220 detects that the output result of the comparison module 210 changes from the second result to the first result during actual operation, it indicates that the commutation time of the motor M has arrived. Figure 7 The rising edge position of the U-phase dead zone voltage shown in the figure indicates that the motor rotor position at that moment is 300°. When the V-phase bridge arm and the W-phase bridge arm are the target bridge arms, the method for determining the motor rotor position is similar to the method for determining the U-phase bridge arm described above and will not be repeated here. This enables the control module to determine the motor rotor position based on the comparison results of the comparison module.

[0071] It should be noted that, since the acquisition device 200 of the embodiment of the present invention only works within the dead time of the inverter, the sampling frequency of the acquisition device 200 can be set based on the dead time of the inverter 100. For example, when the inverter 100 is set according to Figure 6 When the three-three conduction mode is used for control, each phase bridge arm performs two commutations in a single control cycle. Therefore, the sampling frequency of the acquisition device 200 can be set to twice the control frequency. For example, when the control frequency of the inverter 100 is 16KHZ, the sampling frequency of the acquisition device 200 can be 32KHZ, which can achieve the effect of determining the motor rotor position within the dead time.

[0072] In some embodiments, the control module 220 is further configured to generate and output an interrupt signal when the motor rotor position is determined, so as to control the motor based on the interrupt signal.

[0073] Specifically, when the motor rotor position is determined, the control module 220 can assume part of the control function of the motor M, that is, provide an interrupt signal to the external controller of the motor. The generated interrupt signal can be as follows: Figure 8 As shown, reference Figure 8 As shown, within one cycle, the control module 220 can generate 6 interrupt signals according to the motor rotor position, and output them in the form of increasing square waves, corresponding to Figure 8 In the figures 0 to 5 shown, the external controller of the motor M can determine the current motor rotor position based on the interrupt signal and perform 6 commutation operations, which is equivalent to commutation once every 60 degrees, to realize the control function of the motor, thereby further reducing the control cost of the motor.

[0074] In some embodiments, the control module 220 is further configured to generate a position signal and store the position signal in a register when the position of the motor rotor is determined, so as to control the motor based on the position signal in the register.

[0075] Specifically, when determining the motor rotor position, the control module 220 can also generate a position signal based on the determined rotor position and store it in a register. The register has the characteristics of easy storage and reading. Therefore, the external controller of the motor M can easily read the position signal from the register to control the motor M based on the position signal in the register, thereby further reducing the control cost of the motor.

[0076] In some embodiments, the control module 220 is further configured to perform open-loop control on the motor using a constant voltage-frequency ratio or a constant current-frequency ratio.

[0077] Specifically, the constant voltage-frequency ratio and the constant current-frequency ratio are both VF open-loop control modes. In the stable state of VF open-loop control, the current phase difference of the inverter 100 has a stable relationship with the phase difference of the rotor position. At this time, determining the rotor position by detecting the current zero crossing point can make the determined rotor position more accurate. Therefore, when the motor is open-loop controlled using a constant voltage-frequency ratio or a constant current-frequency ratio, the motor rotor position determined by the acquisition device of the embodiment of the present invention is more accurate, thereby improving the accuracy of the acquisition device.

[0078] It should be noted that the motor rotor position acquisition device 200 of the aforementioned multiple embodiments of the invention can be integrated into a chip, so that the chip can integrate the function of acquiring the motor rotor position and has the advantages of low control cost and high reliability, thereby optimizing the chip design.

[0079] In summary, according to the motor rotor position acquisition device of the embodiment of the present invention, by using the comparison module to compare the dead zone voltage of the target bridge arm with the reference voltage within the dead zone time of the inverter, and outputting the comparison result, the motor rotor position is determined based on the comparison result by the control module, thereby realizing the function of acquiring the motor rotor position without the need for a sensor. At the same time, the logic for determining the rotor position is simple, and there is no need to measure the inductance, magnetic flux and other parameters of the motor; in addition, the control module can also send an interrupt signal or generate a position signal and write it into the register when determining the motor rotor position, so that the external controller of the motor can acquire the rotor position of the motor, thereby effectively reducing the control cost of the motor and improving the reliability of the function of acquiring the motor rotor position.

[0080] Corresponding to the above embodiment, the embodiment of the present invention further provides a chip, referring to Figure 8 As shown, the chip 1000 includes the aforementioned motor rotor position acquisition device 200 .

[0081] According to the chip of the embodiment of the present invention, through the aforementioned motor rotor position acquisition device, the function of acquiring the motor rotor position can be realized when the motor is working without the need for a sensor. At the same time, the logic for determining the rotor position is simple, and there is no need to measure the motor's parameters such as inductance and magnetic flux. In addition, when determining the motor rotor position, an interrupt signal can be issued or a position signal can be generated and written into a register to control the motor, thereby effectively reducing the control cost of the motor and improving the reliability of the function of acquiring the motor rotor position.

[0082] Corresponding to the above embodiment, the embodiment of the present invention further provides an electrical device, referring to Figure 10a-10b As shown, the electrical device 10000 includes the aforementioned motor rotor position acquisition device 200 , or the aforementioned chip 1000 .

[0083] According to an embodiment of the present invention, an electrical device includes the motor rotor position acquisition device or chip in any of the above embodiments, wherein the electrical device can be an air conditioner, a refrigerator, a compressor and other devices. These electrical appliances can obtain the motor rotor position without a sensor through the aforementioned motor rotor position acquisition device or the aforementioned chip when the motor is working, and send an interrupt signal or generate a position signal to write into a register when the motor rotor position is determined, so as to control the motor. At the same time, the logic for determining the rotor position is simple and does not require measuring the inductance, magnetic flux and other parameters of the motor; in addition, when the motor rotor position is determined, an interrupt signal can be sent or a position signal can be generated to write into a register to control the motor, thereby effectively reducing the control cost of the motor and improving the reliability of the function of obtaining the motor rotor position.

[0084] Corresponding to the above embodiment, the embodiment of the present invention further provides a method for obtaining the position of a motor rotor, which is applied to Figure 1 The inverter 100 shown in FIG. Figure 11 As shown, the method includes:

[0085] S11, during the dead time of the inverter, compare the dead-zone voltage of the target bridge arm with the reference voltage and output the comparison result, wherein the target bridge arm is the 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-zone voltage is the voltage generated on the corresponding bridge arm by the current flowing through the freewheeling diode during the dead time.

[0086] S12, determining the motor rotor position based on the comparison result.

[0087] According to an embodiment of the present invention, the method further includes: comparing the dead-zone voltage when the corresponding phase bridge arm is used as the target bridge arm with a reference voltage within the dead-zone time, and outputting the comparison result.

[0088] According to an embodiment of the present invention, the method further includes: obtaining, by a single-ended voltage sampling circuit, a dead-zone voltage when the corresponding bridge arm serves as the target bridge arm within the dead-zone time.

[0089] According to one embodiment of the present invention, the reference voltage is determined based on the DC bus voltage of the inverter and the voltage sampling ratio of the single-ended voltage sampling circuit.

[0090] According to one embodiment of the present invention, the method further includes: determining the motor rotor position when the comparison result switches from a first result to a second result, or from a second result to a first result, wherein the first result is a result corresponding to a dead zone voltage being greater than a reference voltage, and the second result is a result corresponding to a dead zone voltage being less than a reference voltage.

[0091] According to an embodiment of the present invention, the method further includes: when the motor rotor position is determined, generating an interrupt signal and outputting the interrupt signal to the outside, so as to control the motor based on the interrupt signal.

[0092] According to an embodiment of the present invention, the method further comprises: when the position of the motor rotor is determined, generating a position signal and storing the position signal in a register, so as to control the motor based on the position signal in the register.

[0093] According to an embodiment of the present invention, the method further includes: performing open-loop control on the motor using a constant voltage-frequency ratio or a constant current-frequency ratio.

[0094] It should be noted that, for the description of the motor rotor position acquisition method in this application, please refer to the description of the motor rotor position acquisition device in this application, and the details will not be repeated here.

[0095] According to the motor rotor position acquisition method of an embodiment of the present invention, the target bridge arm dead-zone voltage is obtained within the dead-zone time of the inverter, and the rotor position is then determined based on the dead-zone voltage, thereby realizing the function of acquiring the motor rotor position without the need for a sensor. At the same time, the rotor position determination logic is simple, and there is no need to measure the inductance, magnetic flux and other parameters of the motor. In addition, an interrupt signal is issued or a position signal is generated and written into a register when the motor rotor position is determined, so that the external controller of the motor can acquire the motor rotor position, thereby effectively reducing the control cost of the motor and improving the reliability of the function of acquiring the motor rotor position.

[0096] 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 rotor position is implemented.

[0097] According to the computer-readable storage medium of an embodiment of the present invention, through the aforementioned motor rotor position acquisition method, the function of acquiring the motor rotor position can be realized when the motor is working without the need for a sensor. At the same time, the logic for determining the rotor position is simple, and there is no need to measure parameters such as the inductance and magnetic flux of the motor. In addition, when determining the motor rotor position, an interrupt signal can be issued or a position signal can be generated and written into a register to control the motor, thereby effectively reducing the control cost of the motor and improving the reliability of the function of acquiring the motor rotor position.

[0098] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, 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 it in another suitable manner if necessary, and then storing it in a computer memory.

[0099] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0100] Throughout this specification, references to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0101] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0102] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0103] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A motor rotor position acquisition device, 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 comparison module, used for comparing the dead zone voltage of the target bridge arm with the reference voltage within the dead zone time of the inverter, and outputting the comparison result, 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; The control module is used to determine the motor rotor position based on the comparison result.

2. The device according to claim 1, characterized in that The comparison module includes a comparator arranged corresponding to each phase bridge arm of the inverter, and the comparator is used to compare the dead zone voltage when the corresponding phase bridge arm is used as the target bridge arm with the reference voltage within the dead zone time, and output the comparison result.

3. The device according to claim 2, characterized in that The comparator 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.

4. The device according to claim 3, characterized in that The reference voltage is determined based on a DC bus voltage of the inverter and a voltage sampling ratio of the single-ended voltage sampling circuit.

5. The device according to any one of claims 1 to 4, characterized in that: The control module is specifically used to determine the motor rotor position when the comparison result switches from a first result to a second result, or switches from the second result to the first result, wherein the first result is a result corresponding to the dead zone voltage being greater than the reference voltage, and the second result is a result corresponding to the dead zone voltage being less than the reference voltage.

6. The device according to claim 1, characterized in that The control module is further configured to generate and output an interrupt signal when the motor rotor position is determined, so as to control the motor based on the interrupt signal.

7. The device according to claim 1, characterized in that The control module is further configured to generate a position signal and store the position signal in a register when the position of the motor rotor is determined, so as to control the motor based on the position signal in the register.

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 rotor position acquisition device according to any one of claims 1-8.

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

11. A method for obtaining a motor rotor position, 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 dead time voltage of the target bridge arm is compared with the reference voltage, and the comparison result is output, 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 comparison result, the motor rotor position is 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 rotor position according to claim 11 is implemented.

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