Motor rotor position detection device and method, motor, compressor and air conditioner

Abstract

The invention discloses a device and method for detecting the position of a rotor of a motor, the motor, a compressor and an air conditioner, and the device comprises a first bipolar Hall element which outputs a first sine differential signal after the rotor of the motor starts to rotate in a set rotation direction; the first comparator is used for comparing the first sine differential signal to obtain a first path of square wave signal; the second bipolar Hall element is used for outputting a second sine differential signal after the rotor of the motor starts to rotate in the set rotation direction; the second comparator is used for comparing the second sine differential signal to obtain a second path of square wave signal; and the control unit calculates the rotor position of the motor according to the first path of square wave signal and the second path of square wave signal in combination with a virtual constant level signal so as to realize the detection of the rotor position of the motor. According to the scheme, the FOC control mode based on the two bipolar Hall elements is adopted to detect the position of the rotor, the detection precision is high, and the cost is low.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and specifically relates to a device and method for detecting the rotor position of a motor, a motor, a compressor and an air conditioner, and more particularly to a device and method for detecting the rotor position based on a bipolar Hall element suitable for a permanent magnet synchronous motor, a permanent magnet synchronous motor, a compressor and an air conditioner. Background Art

[0002] With the mature development of technology in the field of home appliances and the rapid advancement of power electronics technology, motors (such as permanent magnet synchronous motors) generally adopt field-oriented control (FOC), which is becoming more and more popular with advantages such as low cost, high efficiency and low noise. The development of sensor technology has driven the rapid growth of permanent magnet synchronous motors in the market. Common sensors for detecting rotor position in the field of home appliances include bipolar Hall elements and Hall ICs (i.e. Hall sensors). Bipolar Hall elements output differential sinusoidal signals, and Hall ICs output square wave signals. The related scheme uses a three-Hall IC-based FOC control method to detect the rotor position, but the installation accuracy error of the three Hall ICs will affect the efficiency and noise of the motor.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The object of the present invention is to provide a motor rotor position detection device and method, a motor, a compressor and an air conditioner, so as to solve the problem that the rotor position is detected by a FOC control method based on three Hall ICs in the related scheme, but the installation accuracy error of the three Hall ICs will affect the efficiency and noise of the motor. By adopting a scheme based on two bipolar Hall elements to detect the rotor position, the efficiency and noise problems of the motor caused by the installation accuracy error of the three Hall ICs can be avoided, the detection accuracy can be improved and the cost can be reduced.

[0005] The present invention provides a rotor position detection device for a motor, wherein the motor has a three-phase winding; the rotor position detection device for the motor comprises: a first bipolar Hall element, a second bipolar Hall element, a first comparator, a second comparator and a control unit; the first bipolar Hall element and the second bipolar Hall element are both arranged on the three-phase winding of the motor; wherein the first bipolar Hall element is used to output a first sinusoidal differential signal after the rotor of the motor starts to rotate in a set rotation direction; the first comparator is used to compare the first sinusoidal differential signal to obtain a first square wave signal; the second bipolar Hall element is used to output a second sinusoidal differential signal after the rotor of the motor starts to rotate in a set rotation direction; the second comparator is used to compare the second sinusoidal differential signal to obtain a second square wave signal; the control unit is used to calculate the rotor position of the motor according to the first square wave signal and the second square wave signal, in combination with a virtual constant level signal, so as to detect the rotor position of the motor.

[0006] In some embodiments, a PCB board is arranged on the three-phase winding of the motor; the first bipolar Hall element and the second bipolar Hall element are both arranged on the PCB board, and the first bipolar Hall element is located at the slot position of the first phase winding and the second phase winding of the three-phase winding of the motor, and the second bipolar Hall element is located at a position rotated counterclockwise by a set mechanical angle from the position of the first bipolar Hall element.

[0007] In some embodiments, the first phase winding is a U-phase winding, and the detection signal for the U-phase winding is the first square wave signal; the second phase winding is a V-phase winding, and the detection signal for the V-phase winding is the second square wave signal; the third phase winding is a W-phase winding, and the detection signal for the W-phase winding is a virtual constant level signal; and / or the set mechanical angle includes: a mechanical angle of 18°.

[0008] In some embodiments, the control unit calculates the rotor position of the motor based on the first square wave signal and the second square wave signal in combination with a virtual constant level signal, including: determining the Hall state of the motor based on the first square wave signal and the second square wave signal in combination with a virtual constant level signal; determining the rotor position of the motor based on the Hall state of the motor.

[0009] In some embodiments, the control unit determines the Hall state of the motor based on the first square wave signal and the second square wave signal in combination with a virtual constant level signal, including: calculating the Hall state of the motor according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal according to the following formula: State = K1*HU+K2*HV+HW; wherein State represents the Hall state of the motor, HU represents the first square wave signal, HV represents the second square wave signal, HW represents the virtual constant level signal, and K1 and K2 are preset calculation coefficients.

[0010] In some embodiments, the control unit determines the rotor position of the motor according to the Hall state of the motor, including: the number of the Hall states of the motor is four, corresponding to the four sectors of the motor; in the process of the Hall state of the motor changing according to the four sectors of the motor, determining the time interval of the four sectors of the motor; within one Hall cycle, determining the rotor speed of the motor according to the time interval of the four sectors of the motor; determining the rotor angle of the motor according to the rotor speed of the motor to determine the rotor position of the motor.

[0011] Matching the above device, the present invention further provides a motor, including: the rotor position detection device of the motor described above.

[0012] Matching the above device, the present invention further provides a compressor, comprising: the above-mentioned motor rotor position detection device.

[0013] Matching the above device, the present invention further provides an air conditioner, comprising: the above-mentioned motor rotor position detection device.

[0014] Matching the above-mentioned device, the present invention provides a method for detecting the rotor position of a motor on another aspect, comprising: after the first bipolar Hall element and the second bipolar Hall element are powered on, after the rotor of the motor starts to rotate in a set rotation direction, obtaining a first square wave signal output by the first comparator, and obtaining a second square wave signal output by the second comparator; wherein the first square wave signal is a square wave signal obtained by comparing the first comparator with the sinusoidal differential signal output by the first bipolar Hall element; the second square wave signal is a square wave signal obtained by comparing the second comparator with the sinusoidal differential signal output by the second bipolar Hall element; according to the first square wave signal and the second square wave signal, and in combination with a virtual constant level signal, the rotor position of the motor is calculated to detect the rotor position of the motor.

[0015] In some embodiments, a PCB board is arranged on the three-phase winding of the motor; the first bipolar Hall element and the second bipolar Hall element are both arranged on the PCB board, and the first bipolar Hall element is located at the slot position of the first phase winding and the second phase winding of the three-phase winding of the motor, and the second bipolar Hall element is located at a position rotated counterclockwise by a set mechanical angle from the position of the first bipolar Hall element.

[0016] In some embodiments, the first phase winding is a U-phase winding, and the detection signal for the U-phase winding is the first square wave signal; the second phase winding is a V-phase winding, and the detection signal for the V-phase winding is the second square wave signal; the third phase winding is a W-phase winding, and the detection signal for the W-phase winding is a virtual constant level signal; and / or the set mechanical angle includes: a mechanical angle of 18°.

[0017] In some embodiments, the rotor position of the motor is calculated based on the first square wave signal and the second square wave signal in combination with a virtual constant level signal, including: determining the Hall state of the motor based on the first square wave signal and the second square wave signal in combination with a virtual constant level signal; determining the rotor position of the motor based on the Hall state of the motor.

[0018] In some embodiments, the Hall state of the motor is determined according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal, including: according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal, the Hall state of the motor is calculated according to the following formula: State = K1*HU+K2*HV+HW; wherein State represents the Hall state of the motor, HU represents the first square wave signal, HV represents the second square wave signal, HW represents the virtual constant level signal, and K1 and K2 are preset calculation coefficients.

[0019] In some embodiments, the rotor position of the motor is determined according to the Hall state of the motor, including: the number of the Hall states of the motor is four, corresponding to the four sectors of the motor; in the process of the Hall state of the motor changing according to the four sectors of the motor, the time interval of the four sectors of the motor is determined; within one Hall cycle, the rotor speed of the motor is determined according to the time interval of the four sectors of the motor; based on the rotor speed of the motor, the rotor angle of the motor is determined to determine the rotor position of the motor.

[0020] Therefore, the solution of the present invention is aimed at the rotor position detection of the motor (such as the permanent magnet synchronous motor), and two bipolar Hall elements (i.e., the U-phase bipolar Hall element and the V-phase bipolar Hall element) are arranged on the three-phase winding of the motor stator. Specifically, the U-phase bipolar Hall element is arranged at the U-phase and V-phase slot positions of the motor stator, and the V-phase bipolar Hall element is arranged counterclockwise by a certain mechanical angle (such as 18°) based on the bipolar Hall element HU; when the motor rotor rotates counterclockwise, four sinusoidal wave signals are obtained through the two bipolar Hall elements, and the four sinusoidal wave signals are converted into two square wave signals through a comparator, W phase is a virtual signal that is always at a low level; the MCU calculates the speed and angle of the motor rotor based on the two square wave signals of the U phase and the V phase and the virtual signal of the W phase that is always at a low level, and converts it into the position information of the motor rotor to realize the position detection of the motor rotor; thus, a solution for detecting the rotor position by adopting the FOC control method based on two bipolar Hall elements, specifically, by adopting two bipolar Hall elements and combining a comparator and an MCU to realize the position detection of the motor rotor, can avoid the efficiency and noise problems of the motor caused by the installation accuracy error of the three Hall ICs, improve the detection accuracy and reduce the cost.

[0021] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of an embodiment of a rotor position detection device for a motor of the present invention;

[0024] Figure 2 It is a schematic diagram of the placement of two bipolar Hall elements, specifically a schematic diagram of a partial cross-sectional structure;

[0025] Figure 3 It is a hardware block diagram of a rotor position detection device for a permanent magnet synchronous motor;

[0026] Figure 4 Schematic diagram of the rotor position signal conversion process, where (a) is the rotor angle θ in the rotor position signal conversion e Schematic diagram of the calculation process, (b) is the rotor angle θ in the rotor position signal conversion e Schematic diagram of output waveform;

[0027] Figure 5 The relationship between the Hall state and the rotor angle is shown in Table 1;

[0028] Figure 6A schematic diagram of a flow chart of an embodiment of a method for detecting a rotor position of a motor of the present invention;

[0029] Figure 7 A flow chart of an embodiment of calculating the rotor position of the motor according to the first square wave signal, the second square wave signal and a virtual constant level signal in the method of the present invention;

[0030] Figure 8 The present invention is a flow chart of an embodiment of determining the rotor position of the motor according to the Hall state of the motor in the method of the present invention.

[0031] In conjunction with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0032] 10-stator; 20-PCB board; 30-bipolar Hall element. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] Considering that the related scheme adopts the FOC control method based on three Hall ICs to detect the rotor position, there is a problem that the installation accuracy error of the three Hall ICs will affect the efficiency and noise of the motor. Specifically, in the related scheme, the three Halls are installed inside the motor at an electrical angle of 120°, but there is a Hall mounting error in the actual production process, which leads to errors in detecting the rotor angle and causing commutation noise in the motor.

[0035] In addition, in the related scheme, the FOC control scheme uses three Hall ICs (i.e. switch Hall) installed inside the motor at an electrical angle of 120°. When the motor rotates one circle, the three Halls generate a total of 6 states (110, 101, 011, 010, 001, 100), i.e. six sectors; since the switch Hall outputs a square wave digital signal, the MCU can directly read the corresponding Hall state. However, if the FOC control method with three bipolar Hall elements is adopted, since the output signal of the bipolar Hall element is a sinusoidal differential signal, the single-chip microcomputer (i.e. MCU) cannot directly process it.

[0036] Therefore, the scheme of the present invention proposes a rotor position detection device for a motor, specifically a rotor position detection device suitable for a permanent magnet synchronous motor, which uses two bipolar Hall elements to detect the motor rotor position information, and uses an external comparator to convert the output signal of the bipolar Hall element (i.e., the two bipolar Hall elements) from a sinusoidal signal to a square wave signal, which is then converted into continuous rotor position information through MCU calculation, thereby improving the accuracy of rotor position detection without affecting the efficiency and noise of the motor.

[0037] According to an embodiment of the present invention, a rotor position detection device for a motor is provided. Figure 1 A schematic structural diagram of an embodiment of the device of the present invention is shown. The motor has a three-phase winding, specifically, the stator 1 of the motor has a three-phase winding; the rotor position detection device of the motor includes: a first bipolar Hall element, a second bipolar Hall element, a first comparator, a second comparator and a control unit, the first bipolar Hall element is such as a bipolar Hall element HU, the second bipolar Hall element is such as a bipolar Hall element HV, the first comparator is such as a comparator 1, the second comparator is such as a comparator 2, and the control unit is such as an MCU; the first bipolar Hall element and the second bipolar Hall element are both arranged on the three-phase winding of the motor, the first comparator is arranged on the output side of the first bipolar Hall element, the second comparator is arranged on the output side of the second bipolar Hall element, and the first comparator and the second comparator are both connected to the control unit; that is, the first bipolar Hall element and the second bipolar Hall element are arranged on the three-phase winding of the motor, the first comparator is arranged on the output side of the first bipolar Hall element, the second comparator is arranged on the output side of the second bipolar Hall element, and the first comparator and the second comparator are both connected to the control unit.

[0038] in,

[0039] The first bipolar Hall element is used to output a first sinusoidal differential signal (such as sinusoidal differential signals HUP and HUN) after the first bipolar Hall element itself is powered on and the rotor of the motor starts to rotate in a set rotation direction.

[0040] The first comparator is used to compare the first sinusoidal differential signal to obtain a first square wave signal (such as square wave signal HU).

[0041] The second bipolar Hall element is used to output a second sinusoidal differential signal (such as sinusoidal differential signals HVP and HVN) after the second bipolar Hall element itself is powered on and the rotor of the motor starts to rotate in a set rotation direction.

[0042] The second comparator is used to compare the second sinusoidal differential signal to obtain a second square wave signal (such as a square wave signal HV).

[0043] The control unit is used to calculate the rotor position of the motor based on the first square wave signal and the second square wave signal in combination with a virtual constant level signal (such as a virtual constant low level signal) to detect the rotor position of the motor.

[0044] That is to say, after the first bipolar Hall element and the second bipolar Hall element are powered on, after the rotor of the motor starts to rotate in the set rotation direction, the first square wave signal output by the first comparator is obtained, and the second square wave signal output by the second comparator is obtained; wherein the first square wave signal is a square wave signal obtained by the first comparator after comparison based on the sinusoidal differential signal output by the first bipolar Hall element; the second square wave signal is a square wave signal obtained by the second comparator after comparison based on the sinusoidal differential signal output by the second bipolar Hall element. Furthermore, the control unit calculates the rotor position of the motor based on the first square wave signal and the second square wave signal, and combines a virtual constant level signal (such as a virtual constant low level signal) to detect the rotor position of the motor.

[0045] The scheme of the present invention relates to the technical field of rotor position detection of permanent magnet synchronous motors, and in particular to a scheme for detecting the rotor position of permanent magnet synchronous motors based on bipolar Hall elements. The scheme of the present invention proposes a rotor position detection scheme suitable for permanent magnet synchronous motors, which uses two bipolar Hall elements to detect the motor rotor position information. Compared with the FOC control method of three Hall ICs in the related scheme, on the one hand, it can reduce the installation accuracy requirements and reduce the efficiency and noise problems of the motor caused by the installation accuracy error of the three Hall ICs; on the other hand, it saves development costs and makes the product more competitive in the market. In addition, since the output signal of the bipolar Hall element is a sinusoidal differential signal, the single-chip microcomputer cannot directly process it; therefore, the scheme of the present invention, while using two bipolar Hall elements to detect the motor rotor position information, uses an external comparator to convert the output signal of the bipolar Hall element from a sinusoidal signal to a square wave signal, and then converts it into continuous rotor position information through MCU calculation, thereby improving the accuracy of rotor position detection and not affecting the efficiency and noise of the motor.

[0046] In some embodiments, a PCB board 2 is provided on the three-phase winding of the motor; the first bipolar Hall element and the second bipolar Hall element are both provided on the PCB board 2, and the first bipolar Hall element is located at a slot position between the first phase winding and the second phase winding of the three-phase winding of the motor, and the second bipolar Hall element is set based on a mechanical angle set by counterclockwise rotation of the first bipolar Hall element, specifically, the second bipolar Hall element is located at a position after rotating counterclockwise by a set mechanical angle from the position of the first bipolar Hall element.

[0047] The solution of the present invention adopts two bipolar Hall elements to detect the motor rotor position information, adopts an external comparator to convert the output signal of the bipolar Hall element (i.e., the two bipolar Hall elements) from a sinusoidal signal to a square wave signal, and then converts it into continuous rotor position information through MCU calculation, thereby improving the accuracy of rotor position detection without affecting the efficiency and noise of the motor.

[0048] In some embodiments, the first phase winding is a U phase winding, and the detection signal for the U phase winding is the first square wave signal; the second phase winding is a V phase winding, and the detection signal for the V phase winding is the second square wave signal; the third phase winding is a W phase winding, and the detection signal for the W phase winding is a virtual constant level signal (such as a virtual constant low level signal). The set mechanical angle includes: a mechanical angle of 18°.

[0049] Figure 2 FIG. 2 is a schematic diagram of the placement of two bipolar Hall elements, specifically a schematic diagram of a partial cross-sectional structure. In the solution of the present invention, the placement of the two bipolar Hall elements 30 (i.e., the U-phase bipolar Hall element HU and the V-phase bipolar Hall element HV) is as follows: Figure 2 As shown, the PCB board 20 is fixed on the three-phase windings of U, V, and W of the permanent magnet synchronous motor stator 10, wherein the bipolar Hall element HU is placed at the U and V phase notches of the permanent magnet synchronous motor stator 10, and the bipolar Hall element HV is placed 18° counterclockwise based on the bipolar Hall element HU. The two bipolar Hall elements 30 detect the rotor position information of the permanent magnet synchronous motor through the above installation method. Among them, the MCU is arranged on the front side of the PCB board 20 (that is, the side of the PCB board 20 away from the three-phase windings of U, V, and W of the permanent magnet synchronous motor stator 10), and two bipolar Hall elements 30 are arranged on the back side of the PCB board 20 (that is, the side of the PCB board 20 close to the three-phase windings of U, V, and W of the permanent magnet synchronous motor stator 10).

[0050] The solution of the present invention uses two linear Hall elements (i.e. bipolar Hall elements) installed at a mechanical angle of 18° to detect the rotor position inside the motor. The mechanical angle interval of the installation = the Hall electrical angle interval / the number of pole pairs. Taking a motor with 5 pairs of poles and 12 slots as an example, the mechanical angle interval of the Hall installation is 90° / 5 = 18°. Figure 2 The example shown. By installing two linear Hall sensors (i.e. bipolar Hall elements) at a mechanical angle of 18° inside the motor for rotor position detection, the Hall angle is hardware compensated at the initial moment, so that the zero crossing point of the Hall signal differs by 30° from the motor back electromotive force (measured data for the solution of the present invention), the motor efficiency can be improved.

[0051] Among them, each phase winding in the three-phase winding of the motor can be equivalent to a resistor and an inductor connected in series. When voltage is applied to each phase winding of the motor, due to the existence of the winding inductance, the voltage phase will lead the current phase, that is, there is a phase difference between the two. At this time, the motor efficiency is not optimal (the motor efficiency is optimal when the phase difference between the back electromotive force voltage and the winding current is 0). It is necessary to detect the Hall angle of the rotor position to control the phase of the winding voltage. The scheme of the present invention is to install two linear Halls (that is, bipolar Hall elements) at a mechanical angle of 18° inside the motor for rotor position detection, so as to perform hardware compensation for the Hall angle at the initial moment, so that the zero crossing point of the Hall signal differs by 30° from the motor back electromotive force, that is, the winding voltage is compensated by 30° in hardware, so that the phase difference between the winding voltage and the winding current is reduced, which can improve the motor efficiency.

[0052] In the scheme of the present invention, based on the FOC control mode of three Hall ICs in the related scheme, the three Hall ICs are replaced by two bipolar Hall elements to detect the rotor position information. Specifically, the three Halls in the related scheme are installed inside the motor at an electrical angle of 120°, but there is a Hall mounting error in the actual production process, resulting in an error in the detection of the rotor angle, which causes the motor to have commutation noise; while the scheme of the present invention uses two linear Halls (i.e. bipolar Hall elements) installed inside the motor at an electrical angle of 90° (i.e. 18° mechanical angle), which can reduce part of the Hall mounting error in the production process, and then convert it into continuous rotor angle information through comparator and MCU calculation, thereby improving the detection accuracy, while further reducing the cost of the product and improving market competitiveness.

[0053] In some implementations, the control unit calculates the rotor position of the motor according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal (such as a virtual constant low level signal), including:

[0054] The control unit is specifically further configured to determine the Hall state of the motor according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal (such as a virtual constant low level signal).

[0055] The control unit is specifically further configured to determine the rotor position of the motor according to the Hall state of the motor.

[0056] The solution of the present invention uses a comparator circuit to convert the output sinusoidal analog signals of two linear Hall elements (ie bipolar Hall elements) into square wave digital signals for MCU detection and calculation. Figure 3 The hardware block diagram of the rotor position detection device of the permanent magnet synchronous motor is shown in FIG. Figure 3 As shown in FIG. 1 , the rotor position detection device of the permanent magnet synchronous motor includes: an MCU, a three-phase inverter module, a comparator 1, a comparator 2 and a current sampling module. Two bipolar Hall elements are arranged according to Figure 2 The method shown is installed inside the permanent magnet synchronous motor to detect the rotor position information, and outputs four sinusoidal voltage signals HUP (i.e., the positive sinusoidal voltage signal output by the U-phase bipolar Hall element HU), HUN (i.e., the negative sinusoidal voltage signal output by the U-phase bipolar Hall element HU), HVP (i.e., the positive sinusoidal voltage signal output by the V-phase bipolar Hall element HV), and HVN (i.e., the negative sinusoidal voltage signal output by the V-phase bipolar Hall element HV).

[0057] See also Figure 2 and Figure 3 In the example shown, the PCB board is Figure 2 The method shown is fixed on the U, V, and W of the permanent magnet synchronous motor stator, where the bipolar Hall element HU is placed at the U and V phase slots of the permanent magnet synchronous motor stator, and the bipolar Hall element HV is rotated 18° counterclockwise. The Hall sensor detects the rotor position information through the above installation method. After the PCB board is powered on, the rotor starts to rotate (taking counterclockwise rotation as an example) and the two bipolar Hall elements 3 output four sinusoidal voltage signals HUP, HUN, HVP, and HVN. Figure 3 In the example shown, comparator 1 and comparator 2 transform the four voltage signals (i.e., four sinusoidal voltage signals HUP, HUN, HVP, HVN) into two square wave digital signals HU and HV. Comparing the amplitudes of the four sinusoidal voltage signals HUP, HUN, HVP, HVN, the specific transformation rules are as follows: when HUP>HUN, comparator 1 outputs HU as a high level; when HUP<HUN, comparator 1 outputs HU as a low level. When HVP>HVN, comparator 2 outputs HV as a high level; when HVP<HVN, comparator 2 outputs HV as a low level.

[0058] exist Figure 3In the example shown, the current sampling module is responsible for collecting the three-phase currents Ia, Ib, and Ic of the permanent magnet synchronous motor (PMSM). The MCU is responsible for calculating the collected HU and HV, as well as the data of Ia, Ib, and Ic, and outputting six PWM signals (specifically PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6) to drive the three-phase inverter module to output a voltage with variable frequency and voltage amplitude, thereby driving the motor to rotate.

[0059] In the scheme of the present invention, an external comparator is used to convert the output signal of the bipolar Hall element from a sinusoidal signal into two square wave signals, which are then converted into continuous rotor position information through MCU calculation, thereby improving the accuracy of rotor position detection. Specifically, since the output signal of the bipolar Hall element is a sinusoidal differential signal, the single-chip microcomputer cannot directly process it; while the scheme of the present invention uses two linear Halls (i.e., bipolar Hall elements) to detect the rotor position, and the linear Halls (i.e., bipolar Hall elements) output sinusoidal differential analog signals, which cannot be directly read by the MCU, and are converted into square wave digital signals through a comparator circuit, and then converted into continuous rotor position information through the MCU reading the Hall state, thereby improving the accuracy of rotor position detection.

[0060] In some embodiments, the control unit determines the Hall state of the motor according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal (such as a virtual constant low level signal), including: the control unit is further configured to calculate the Hall state of the motor according to the following formula according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal (such as a virtual constant low level signal):

[0061] State = K1*HU+K2*HV+HW;

[0062] Among them, State represents the Hall state of the motor, HU represents the first square wave signal, HV represents the second square wave signal, HW represents a virtual constant level signal, and K1 and K2 are both preset calculation coefficients.

[0063] Figure 5 The relationship between the Hall state and the rotor angle is shown in Table 1. Figure 5 As shown, comparator 1 and comparator 2 output two square wave signals HU and HV, where HW is a virtual signal that is always at a low level and is input to the MCU to participate in the rotor angle θ e Calculation. The Hall state calculation formula is State=4*HU+2*HV+HW. When the Hall state State=2, θ e =-24576; when State = 6, θ e =-8192; when Hall state State = 4, θe =8192; when State = 0, θ e =24576; then calculate the continuous rotor angle θ e Participate in FOC calculation, rotor angle θ in rotor position signal conversion e Calculation process and output waveform see Figure 4 .

[0064] Of course, when the permanent magnet synchronous motor rotor rotates, virtual sensors can also be used to detect the rotor position information, that is, no Hall sensor control, such as synovial observer, Romberg observer, etc., by collecting the three-phase current of the motor to calculate the back electromotive force to indirectly obtain the continuous rotor angle. However, this method has the problem that the rotor position estimation is inaccurate when the motor is at low speed, which can easily cause abnormalities such as loss of step and shutdown.

[0065] In the scheme of the present invention, two bipolar Hall elements are used, and the U-phase Hall is placed at the U and V slots of the stator. The Hall signal is converted by a comparator to output a continuous rotor angle. Specifically, in the scheme of the present invention, the linear bipolar Hall element HU is placed at the U and V phase slots of the permanent magnet synchronous motor stator, and the linear bipolar Hall element HV is rotated 18° counterclockwise (the electrical angle is 90°). An external comparator is used to convert the output signals of the two bipolar Hall elements from sinusoidal signals to square wave signals, which are then converted into continuous rotor position information through MCU calculation, thereby improving the accuracy of rotor position detection.

[0066] In some implementations, the control unit determines the rotor position of the motor according to the Hall state of the motor, including:

[0067] The control unit is further specifically configured so that the number of the Hall states of the motor is four, corresponding to the four sectors of the motor; and in the process of the Hall state of the motor changing according to the four sectors of the motor, the time intervals of the four sectors of the motor are determined.

[0068] The control unit is further specifically configured to determine the rotor speed of the motor according to the time intervals of the four sectors of the motor within one Hall cycle.

[0069] The control unit is specifically further configured to determine the rotor angle of the motor according to the rotor speed of the motor, so as to determine the rotor position of the motor.

[0070] Figure 4 Schematic diagram of the rotor position signal conversion process, where (a) is the rotor angle θ in the rotor position signal conversion e Schematic diagram of the calculation process, (b) is the rotor angle θ in the rotor position signal conversion e Schematic diagram of the output waveform. Figure 4 As shown in the figure, when the rotor rotates counterclockwise, the two bipolar Hall elements output four sinusoidal signals. Comparator 1 and Comparator 2 convert the four sinusoidal signals into two square wave signals HU and HV, where HW is a virtual signal that is always at a low level. The MCU calculates the continuous rotor angle information θ e That is, when the rotor rotates, within a Hall electrical cycle (0-360°), the Hall state changes according to four sectors: 010->110->100->000. The time intervals for MCU to read these four sectors are T1, T2, T3, and T4. The total time interval of a Hall cycle is △T=T1+T2+T3+T4, and the rotor speed SPEED is:

[0071]

[0072] Rotor angle θ e for:

[0073]

[0074] In the solution of the present invention, the Hall state is read in the order of 100->110->010->000, and one Hall cycle is divided into four sectors. e In the electrical cycle, the rotor angle θ e Accumulate from -32768 to +32767 (the q15 format of the rotor angle represents the rotor 0 to 360 degrees), thereby realizing continuous reading of the rotor angle and achieving higher precision rotor position detection. Figure 4 In the example shown, the rotor speed SPEED is calculated in four sectors of two bipolar Hall elements and averaged over a Hall cycle △T and then integrated to calculate the rotor angle θ. e , further improving the reliability and accuracy of rotor position detection in the solution of the present invention.

[0075] Among them, see Figure 3 In the example shown, when the rotor rotates, in one Hall cycle △T, the rotor electrical angle θ e From 0->360°, the corresponding Hall state changes from 100->110->010->000, and the corresponding rotor angle changes from -32768->+32767. This q15 format (i.e. 2^15=32768) data is convenient for the microcontroller unit (MCU) to be used in the field-oriented control (FOC), and the accuracy is also higher. For example: the data in q15 format is as follows: θ e =-32768 represents the rotor electrical angle θ e is 0°, θe =-24576 represents the rotor electrical angle θ e is 45°, θ e =-8192 represents the rotor electrical angle θ e is 135°, θ e =8192 represents the rotor electrical angle θ e is 225°, θ e =24576 represents the rotor electrical angle θ e is 315°, θ e =32767 represents the rotor electrical angle θ e It is 360°.

[0076] The Hall state is read continuously as 100->110->010->000. By calculating the HU and HV signal jump times T1, T2, T3, and T4 (the discontinuous rotor angles in the four states can be obtained, see Table 1 for details), the rotor speed SPEED is calculated first, and then the continuous rotor angle (i.e. θ e Accumulated from -32768 to +32767) to achieve higher precision rotor angle:

[0077]

[0078] The technical solution of the present invention is adopted, through the rotor position detection of the motor (such as the permanent magnet synchronous motor), two bipolar Hall elements (namely the U-phase bipolar Hall element and the V-phase bipolar Hall element) are arranged on the three-phase winding of the motor stator, specifically, the U-phase bipolar Hall element is arranged at the U-phase and V-phase slot positions of the motor stator, and the V-phase bipolar Hall element is arranged by rotating the bipolar Hall element HU counterclockwise by a certain mechanical angle (such as 18°); when the motor rotor rotates counterclockwise, four sinusoidal wave signals are obtained through the two bipolar Hall elements, and the four sinusoidal wave signals are converted into two square wave signals through a comparator, The W phase is a virtual signal that is always at a low level. The MCU calculates the speed and angle of the motor rotor based on the two square wave signals of the U phase and the V phase and the virtual signal of the W phase that is always at a low level, and converts them into the position information of the motor rotor to realize the position detection of the motor rotor. Thus, the rotor position is detected by adopting a FOC control method based on two bipolar Hall elements. Specifically, two bipolar Hall elements are adopted in combination with a comparator and an MCU to realize the position detection of the motor rotor, which can avoid the efficiency and noise problems of the motor caused by the installation accuracy error of the three Hall ICs, improve the detection accuracy and reduce the cost.

[0079] According to an embodiment of the present invention, a motor corresponding to a rotor position detection device of the motor is also provided. The motor may include: the rotor position detection device of the motor described above.

[0080] Since the processing and functions implemented by the motor of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0081] According to an embodiment of the present invention, a compressor corresponding to the rotor position detection device of the motor is also provided. The compressor may include: the rotor position detection device of the motor described above.

[0082] Since the processing and functions implemented by the compressor of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0083] According to an embodiment of the present invention, an air conditioner corresponding to the rotor position detection device of a motor is also provided. The air conditioner may include: the rotor position detection device of the motor described above.

[0084] Since the processing and functions implemented by the air conditioner of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0085] According to an embodiment of the present invention, a method for detecting the rotor position of a motor corresponding to the rotor position detection device of the motor is also provided. Figure 6 The flowchart of an embodiment of the method of the present invention is shown in FIG. The method for detecting the rotor position of a motor may include: steps S110 to S120.

[0086] At step S110, after the first bipolar Hall element and the second bipolar Hall element are powered on and after the rotor of the motor starts to rotate in a set rotation direction, a first square wave signal output by the first comparator is obtained, and a second square wave signal output by the second comparator is obtained; wherein, the first square wave signal is a square wave signal obtained by comparing the first comparator with the sinusoidal differential signal output by the first bipolar Hall element; and the second square wave signal is a square wave signal obtained by comparing the second comparator with the sinusoidal differential signal output by the second bipolar Hall element.

[0087] In step S120, the rotor position of the motor is calculated based on the first square wave signal and the second square wave signal in combination with a virtual constant level signal (such as a virtual constant low level signal) to detect the rotor position of the motor.

[0088] The solution of the present invention uses two bipolar Hall elements to detect the motor rotor position information. Compared with the FOC control method of three Hall ICs in the related solution, on the one hand, it can reduce the installation accuracy requirements and reduce the efficiency and noise problems of the motor caused by the installation accuracy error of the three Hall ICs; on the other hand, it saves development costs and makes the product more competitive in the market. In addition, since the output signal of the bipolar Hall element is a sinusoidal differential signal, the single-chip microcomputer cannot directly process it; therefore, the solution of the present invention, while using two bipolar Hall elements to detect the motor rotor position information, uses an external comparator to convert the output signal of the bipolar Hall element from a sinusoidal signal to a square wave signal, and then converts it into continuous rotor position information through MCU calculation, thereby improving the accuracy of rotor position detection and not affecting the efficiency and noise of the motor.

[0089] In some embodiments, a PCB board 2 is provided on the three-phase winding of the motor; the first bipolar Hall element and the second bipolar Hall element are both provided on the PCB board 2, and the first bipolar Hall element is located at a slot position between the first phase winding and the second phase winding of the three-phase winding of the motor, and the second bipolar Hall element is set based on a mechanical angle set by counterclockwise rotation of the first bipolar Hall element, specifically, the second bipolar Hall element is located at a position after rotating counterclockwise by a set mechanical angle from the position of the first bipolar Hall element.

[0090] The solution of the present invention adopts two bipolar Hall elements to detect the motor rotor position information, adopts an external comparator to convert the output signal of the bipolar Hall element (i.e., the two bipolar Hall elements) from a sinusoidal signal to a square wave signal, and then converts it into continuous rotor position information through MCU calculation, thereby improving the accuracy of rotor position detection without affecting the efficiency and noise of the motor.

[0091] In some embodiments, the first phase winding is a U phase winding, and the detection signal for the U phase winding is the first square wave signal; the second phase winding is a V phase winding, and the detection signal for the V phase winding is the second square wave signal; the third phase winding is a W phase winding, and the detection signal for the W phase winding is a virtual constant level signal (such as a virtual constant low level signal). The set mechanical angle includes: a mechanical angle of 18°.

[0092] Figure 2 FIG. 2 is a schematic diagram of the placement of two bipolar Hall elements, specifically a schematic diagram of a partial cross-sectional structure. In the solution of the present invention, the placement of the two bipolar Hall elements 30 (i.e., the U-phase bipolar Hall element HU and the V-phase bipolar Hall element HV) is as follows: Figure 2As shown, the PCB board 20 is fixed on the three-phase windings of U, V, and W of the permanent magnet synchronous motor stator 10, wherein the bipolar Hall element HU is placed at the U and V phase notches of the permanent magnet synchronous motor stator 10, and the bipolar Hall element HV is placed 18° counterclockwise based on the bipolar Hall element HU. The two bipolar Hall elements 30 detect the rotor position information of the permanent magnet synchronous motor through the above installation method. Among them, the MCU is arranged on the front side of the PCB board 20 (that is, the side of the PCB board 20 away from the three-phase windings of U, V, and W of the permanent magnet synchronous motor stator 10), and two bipolar Hall elements 30 are arranged on the back side of the PCB board 20 (that is, the side of the PCB board 20 close to the three-phase windings of U, V, and W of the permanent magnet synchronous motor stator 10).

[0093] The solution of the present invention uses two linear Hall elements (i.e. bipolar Hall elements) installed at a mechanical angle of 18° to detect the rotor position inside the motor. The mechanical angle interval of the installation = the Hall electrical angle interval / the number of pole pairs. Taking a motor with 5 pairs of poles and 12 slots as an example, the mechanical angle interval of the Hall installation is 90° / 5 = 18°. Figure 2 The example shown. By installing two linear Hall sensors (i.e. bipolar Hall elements) at a mechanical angle of 18° inside the motor for rotor position detection, the Hall angle is hardware compensated at the initial moment, so that the zero crossing point of the Hall signal differs by 30° from the motor back electromotive force (measured data for the solution of the present invention), the motor efficiency can be improved.

[0094] In the scheme of the present invention, based on the FOC control mode of three Hall ICs in the related scheme, the three Hall ICs are replaced by two bipolar Hall elements to detect the rotor position information. Specifically, the three Halls in the related scheme are installed inside the motor at an electrical angle of 120°, but there is a Hall mounting error in the actual production process, resulting in an error in the detection of the rotor angle, which causes the motor to have commutation noise; while the scheme of the present invention uses two linear Halls (i.e. bipolar Hall elements) installed inside the motor at an electrical angle of 90° (i.e. 18° mechanical angle), which can reduce part of the Hall mounting error in the production process, and then convert it into continuous rotor angle information through comparator and MCU calculation, thereby improving the detection accuracy, while further reducing the cost of the product and improving market competitiveness.

[0095] In some embodiments, the specific process of calculating the rotor position of the motor in step S120 based on the first square wave signal and the second square wave signal in combination with a virtual constant level signal (such as a virtual constant low level signal) is described in the following exemplary embodiment.

[0096] Combine the following Figure 7The method of the present invention is shown as a flow chart of an embodiment of calculating the rotor position of the motor according to the first square wave signal, the second square wave signal and a virtual constant level signal (such as a virtual constant low level signal), further illustrating the specific process of calculating the rotor position of the motor according to the first square wave signal, the second square wave signal and a virtual constant level signal (such as a virtual constant low level signal) in step S120, including: steps S210 to S220.

[0097] Step S210, determining the Hall state of the motor according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal (such as a virtual constant low level signal).

[0098] Step S220: determining the rotor position of the motor according to the Hall state of the motor.

[0099] The solution of the present invention uses a comparator circuit to convert the output sinusoidal analog signals of two linear Hall elements (ie bipolar Hall elements) into square wave digital signals for MCU detection and calculation. Figure 3 The hardware block diagram of the rotor position detection device of the permanent magnet synchronous motor is shown in FIG. Figure 3 As shown in FIG. 1 , the rotor position detection device of the permanent magnet synchronous motor includes: an MCU, a three-phase inverter module, a comparator 1, a comparator 2 and a current sampling module. Two bipolar Hall elements are arranged according to Figure 2 The method shown is installed inside the permanent magnet synchronous motor to detect the rotor position information, and outputs four sinusoidal voltage signals HUP (i.e., the positive sinusoidal voltage signal output by the U-phase bipolar Hall element HU), HUN (i.e., the negative sinusoidal voltage signal output by the U-phase bipolar Hall element HU), HVP (i.e., the positive sinusoidal voltage signal output by the V-phase bipolar Hall element HV), and HVN (i.e., the negative sinusoidal voltage signal output by the V-phase bipolar Hall element HV).

[0100] See also Figure 2 and Figure 3 In the example shown, the PCB board is Figure 2 The method shown is fixed on the U, V, and W of the permanent magnet synchronous motor stator, where the bipolar Hall element HU is placed at the U and V phase slots of the permanent magnet synchronous motor stator, and the bipolar Hall element HV is rotated 18° counterclockwise. The Hall sensor detects the rotor position information through the above installation method. After the PCB board is powered on, the rotor starts to rotate (taking counterclockwise rotation as an example) and the two bipolar Hall elements 3 output four sinusoidal voltage signals HUP, HUN, HVP, and HVN. Figure 3In the example shown, comparator 1 and comparator 2 transform the four voltage signals (i.e., four sinusoidal voltage signals HUP, HUN, HVP, HVN) into two square wave digital signals HU and HV. Comparing the amplitudes of the four sinusoidal voltage signals HUP, HUN, HVP, HVN, the specific transformation rules are as follows: when HUP>HUN, comparator 1 outputs HU as a high level; when HUP<HUN, comparator 1 outputs HU as a low level. When HVP>HVN, comparator 2 outputs HV as a high level; when HVP<HVN, comparator 2 outputs HV as a low level.

[0101] exist Figure 3 In the example shown, the current sampling module is responsible for collecting the three-phase currents Ia, Ib, and Ic of the permanent magnet synchronous motor (PMSM). The MCU is responsible for calculating the collected HU and HV, as well as the data of Ia, Ib, and Ic, and outputting six PWM signals (specifically PWM1, PWM2, PWM3, PWM4, PWM5, and PWM6) to drive the three-phase inverter module to output a voltage with variable frequency and voltage amplitude, thereby driving the motor to rotate.

[0102] In the scheme of the present invention, an external comparator is used to convert the output signal of the bipolar Hall element from a sinusoidal signal into two square wave signals, which are then converted into continuous rotor position information through MCU calculation, thereby improving the accuracy of rotor position detection. Specifically, since the output signal of the bipolar Hall element is a sinusoidal differential signal, the single-chip microcomputer cannot directly process it; while the scheme of the present invention uses two linear Halls (i.e., bipolar Hall elements) to detect the rotor position, and the linear Halls (i.e., bipolar Hall elements) output sinusoidal differential analog signals, which cannot be directly read by the MCU, and are converted into square wave digital signals through a comparator circuit, and then converted into continuous rotor position information through the MCU reading the Hall state, thereby improving the accuracy of rotor position detection.

[0103] In some embodiments, in step S210, according to the first square wave signal and the second square wave signal, in combination with a virtual constant level signal (such as a virtual constant low level signal), determining the Hall state of the motor includes: according to the first square wave signal and the second square wave signal, in combination with a virtual constant level signal (such as a virtual constant low level signal), calculating the Hall state of the motor according to the following formula:

[0104] State = K1*HU+K2*HV+HW;

[0105] Among them, State represents the Hall state of the motor, HU represents the first square wave signal, HV represents the second square wave signal, HW represents a virtual constant level signal, and K1 and K2 are both preset calculation coefficients.

[0106] Figure 5 The relationship between the Hall state and the rotor angle is shown in Table 1. Figure 5 As shown, comparator 1 and comparator 2 output two square wave signals HU and HV, where HW is a virtual signal that is always at a low level and is input to the MCU to participate in the rotor angle θ e Calculation. The Hall state calculation formula is State=4*HU+2*HV+HW. When the Hall state State=2, θ e =-24576; when State = 6, θ e =-8192; when Hall state State = 4, θ e =8192; when State = 0, θ e =24576; then calculate the continuous rotor angle θ e Participate in FOC calculation, rotor angle θ in rotor position signal conversion e Calculation process and output waveform see Figure 4 .

[0107] Of course, when the permanent magnet synchronous motor rotor rotates, virtual sensors can also be used to detect the rotor position information, that is, no Hall sensor control, such as synovial observer, Romberg observer, etc., by collecting the three-phase current of the motor to calculate the back electromotive force to indirectly obtain the continuous rotor angle. However, this method has the problem that the rotor position estimation is inaccurate when the motor is at low speed, which can easily cause abnormalities such as loss of step and shutdown.

[0108] In the scheme of the present invention, two bipolar Hall elements are used, and the U-phase Hall is placed at the U and V slots of the stator. The Hall signal is converted by a comparator to output a continuous rotor angle. Specifically, in the scheme of the present invention, the linear bipolar Hall element HU is placed at the U and V phase slots of the permanent magnet synchronous motor stator, and the linear bipolar Hall element HV is rotated 18° counterclockwise (the electrical angle is 90°). An external comparator is used to convert the output signals of the two bipolar Hall elements from sinusoidal signals to square wave signals, which are then converted into continuous rotor position information through MCU calculation, thereby improving the accuracy of rotor position detection.

[0109] In some implementations, the specific process of determining the rotor position of the motor according to the Hall state of the motor in step S220 is described in the following exemplary embodiment.

[0110] Combine the following Figure 8 The flowchart of an embodiment of determining the rotor position of the motor according to the Hall state of the motor in the method of the present invention further illustrates the specific process of determining the rotor position of the motor according to the Hall state of the motor in step S220, including: steps S310 to S330.

[0111] Step S310, the number of the Hall states of the motor is four, corresponding to the four sectors of the motor; in the process of the Hall state of the motor changing according to the four sectors of the motor, the time intervals of the four sectors of the motor are determined.

[0112] Step S320, determining the rotor speed of the motor according to the time intervals of the four sectors of the motor within one Hall cycle.

[0113] Step S340, determining the rotor angle of the motor according to the rotor speed of the motor to determine the rotor position of the motor.

[0114] Figure 4 Schematic diagram of the rotor position signal conversion process, where (a) is the rotor angle θ in the rotor position signal conversion e Schematic diagram of the calculation process, (b) is the rotor angle θ in the rotor position signal conversion e Schematic diagram of the output waveform. Figure 4 As shown in the figure, when the rotor rotates counterclockwise, the two bipolar Hall elements output four sinusoidal signals. Comparator 1 and Comparator 2 convert the four sinusoidal signals into two square wave signals HU and HV, where HW is a virtual signal that is always at a low level. The MCU calculates the continuous rotor angle information θ e That is, when the rotor rotates, within a Hall electrical cycle (0-360°), the Hall state changes according to four sectors: 010->110->100->000. The time intervals for MCU to read these four sectors are T1, T2, T3, and T4. The total time interval of a Hall cycle is △T=T1+T2+T3+T4, and the rotor speed SPEED is:

[0115]

[0116] Rotor angle θ e for:

[0117]

[0118] In the solution of the present invention, the Hall state is read in the order of 100->110->010->000, and one Hall cycle is divided into four sectors. e In the electrical cycle, the rotor angle θ e Accumulate from -32768 to +32767 (the q15 format of the rotor angle represents the rotor 0 to 360 degrees), thereby realizing continuous reading of the rotor angle and achieving higher precision rotor position detection. Figure 4In the example shown, the rotor speed SPEED is calculated in four sectors of two bipolar Hall elements and averaged over a Hall cycle △T and then integrated to calculate the rotor angle θ. e , further improving the reliability and accuracy of rotor position detection in the solution of the present invention.

[0119] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned motor, compressor and air conditioner, for the details not exhaustive in the description of this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0120] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0121] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A rotor position detection device for a motor, characterized in that: The motor has a three-phase winding; the rotor position detection device of the motor includes: a first bipolar Hall element, a second bipolar Hall element, a first comparator, a second comparator and a control unit; the first bipolar Hall element and the second bipolar Hall element are both arranged on the three-phase winding of the motor; wherein, The first bipolar Hall element is used to output a first sinusoidal differential signal after the rotor of the motor starts to rotate in a set rotation direction; The first comparator is used to compare the first sinusoidal differential signal to obtain a first square wave signal; The second bipolar Hall element is used to output a second sinusoidal differential signal after the rotor of the motor starts to rotate in a set rotation direction; The second comparator is used to compare the second sinusoidal differential signal to obtain a second square wave signal; The control unit is used to calculate the rotor position of the motor according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal, so as to detect the rotor position of the motor.

2. The rotor position detection device of a motor according to claim 1, characterized in that: A PCB board (2) is arranged on the three-phase winding of the motor; the first bipolar Hall element and the second bipolar Hall element are both arranged on the PCB board (2), and the first bipolar Hall element is located at a slot position between the first phase winding and the second phase winding of the three-phase winding of the motor, and the second bipolar Hall element is located at a position rotated counterclockwise by a set mechanical angle from the position where the first bipolar Hall element is located.

3. The rotor position detection device of a motor according to claim 2, characterized in that: in, The first phase winding is a U phase winding, and the detection signal for the U phase winding is the first square wave signal; the second phase winding is a V phase winding, and the detection signal for the V phase winding is the second square wave signal; the third phase winding is a W phase winding, and the detection signal for the W phase winding is a virtual constant level signal; and / or, The set mechanical angle includes: 18° mechanical angle.

4. The rotor position detection device for a motor according to any one of claims 1 to 3, characterized in that: The control unit calculates the rotor position of the motor according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal, including: Determining the Hall state of the motor according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal; The rotor position of the motor is determined according to the Hall state of the motor.

5. The rotor position detection device of a motor according to claim 4, characterized in that: The control unit determines the Hall state of the motor according to the first square wave signal and the second square wave signal in combination with a virtual constant level signal, including: According to the first square wave signal and the second square wave signal, and in combination with the virtual constant level signal, the Hall state of the motor is calculated according to the following formula: State = K1*HU+K2*HV+HW; Among them, State represents the Hall state of the motor, HU represents the first square wave signal, HV represents the second square wave signal, HW represents a virtual constant level signal, and K1 and K2 are both preset calculation coefficients.

6. The rotor position detection device of a motor according to claim 4, characterized in that: The control unit determines the rotor position of the motor according to the Hall state of the motor, including: The number of the Hall states of the motor is four, corresponding to the four sectors of the motor; in the process of the Hall state of the motor changing according to the four sectors of the motor, the time intervals of the four sectors of the motor are determined; Determining the rotor speed of the motor according to the time intervals of the four sectors of the motor within a Hall cycle; The rotor angle of the motor is determined according to the rotor speed of the motor to determine the rotor position of the motor.

7. A motor, characterized in that: include: The rotor position detection device for an electric motor according to any one of claims 1 to 6.

8. A compressor, characterized in that: include: The rotor position detection device for an electric motor according to any one of claims 1 to 6.

9. An air conditioner, characterized in that: include: The rotor position detection device for an electric motor according to any one of claims 1 to 6.

10. A method for detecting the rotor position of a motor corresponding to the rotor position detection device of a motor according to any one of claims 1 to 6, characterized in that: include: After the first bipolar Hall element and the second bipolar Hall element are powered on, and after the rotor of the motor starts to rotate in a set rotation direction, a first square wave signal output by the first comparator is obtained, and a second square wave signal output by the second comparator is obtained; wherein the first square wave signal is a square wave signal obtained by the first comparator after comparison based on the sinusoidal differential signal output by the first bipolar Hall element; and the second square wave signal is a square wave signal obtained by the second comparator after comparison based on the sinusoidal differential signal output by the second bipolar Hall element; The rotor position of the motor is calculated based on the first square wave signal and the second square wave signal in combination with a virtual constant level signal to detect the rotor position of the motor.

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