Motor Rotor Positioning Device, Driving Assembly and Power Tool

Abstract

The present disclosure relates to a motor rotor position positioning device, a drive assembly, and a power tool. The device includes: a three-phase motor including a rotor and a stator; a three-phase full-bridge inverter; a drive module electrically connected to the three-phase full-bridge inverter and configured to output a preset plurality of sets of control signals to control the conduction states of the transistors of the three-phase full-bridge inverter; and a positioning module electrically connected to the three-phase full-bridge inverter and configured to collect a plurality of busbar currents of the motor under the control of the plurality of sets of control signals and determine the position of the rotor using the plurality of busbar currents. The motor rotor position positioning device according to the embodiments of the present disclosure does not require a dedicated position sensor to be provided in the motor, can achieve the positioning of the rotor position, improves the positioning accuracy compared with the related art, and saves costs and space.

Description

Technical Field

[0001] The present disclosure relates to the technical field of motor control, and in particular, to a motor rotor position positioning device, a drive assembly, and a power tool. Background Art

[0002] Due to its good speed regulation performance, wide speed regulation range, and simple speed regulation method, the DC motor is widely used in high-performance speed regulation systems. However, the commutator of the brushed motor inevitably has disadvantages such as commutation sparks, mechanical noise, and poor maintainability. To make up for these deficiencies of the brushed DC motor, the brushless DC motor (BrushLess DC Motor, abbreviated as BLDC) came into being. The brushless DC motor not only well makes up for the deficiencies of the brushed DC motor, but also can be comparable to the brushed DC motor in performance, so it is more and more widely used in high-performance servo and household appliances and other fields.

[0003] Normally, a brushless DC motor has three position sensors fixed on the stator to detect the magnetic pole position of the rotor relative to the stator. However, the installation of the position sensor will increase the additional cost and volume, and will be affected by environmental temperature, humidity, etc. Therefore, the control method without a position sensor (SensorLess) has been paid more and more attention. For the control of the brushless DC motor without a position sensor, the related technology usually uses the back electromotive force detection method to control the brushless DC motor without a position sensor. However, the back electromotive force method has a very fatal defect, that is, the accurate back electromotive force cannot be obtained in the motor starting state and the low-speed state where the back electromotive force is very small, and thus the relative position of the rotor cannot be accurately obtained. Summary of the Invention

[0004] In view of this, the present disclosure provides a motor rotor position positioning device, a drive assembly, and a power tool, which do not require a dedicated position sensor, can obtain the accurate relative position of the rotor, and realize the precise control of the motor.

[0005] According to one aspect of the present disclosure, a motor rotor position positioning device is provided, and the device includes:

[0006] A three-phase motor, including a rotor and a stator;

[0007] Three-phase full-bridge inverter, including a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor. The first transistor and the fourth transistor form a first bridge arm, the second transistor and the fifth transistor form a second bridge arm, and the third transistor and the sixth transistor form a third bridge arm. Wherein, one ends of the windings of the stator are electrically connected, and the other ends of the windings are respectively electrically connected between the first transistor and the fourth transistor, between the second transistor and the fifth transistor, and between the third transistor and the sixth transistor;

[0008] Drive module, electrically connected to the three-phase full-bridge inverter, for outputting a preset multiple sets of control signals to control the conduction states of the transistors of the three-phase full-bridge inverter;

[0009] Positioning module, electrically connected to the three-phase full-bridge inverter, for collecting multiple bus currents of the motor under the control of multiple sets of control signals and determining the position of the rotor using the multiple bus currents.

[0010] In a possible implementation, the preset multiple sets of control signals include at least one of the following:

[0011] First control signal, controlling the first transistor, the fifth transistor, and the sixth transistor to conduct, and controlling the second transistor, the third transistor, and the fourth transistor to turn off;

[0012] Second control signal, controlling the first transistor and the sixth transistor to conduct, and controlling the second transistor, the third transistor, the fourth transistor, and the fifth transistor to turn off;

[0013] Third control signal, controlling the first transistor, the second transistor, and the sixth transistor to conduct, and controlling the third transistor, the fourth transistor, and the fifth transistor to turn off;

[0014] Fourth control signal, controlling the second transistor and the sixth transistor to conduct, and controlling the first transistor, the third transistor, the fourth transistor, and the fifth transistor to turn off;

[0015] Fifth control signal, controlling the second transistor, the fourth transistor, and the sixth transistor to conduct, and controlling the first transistor, the third transistor, and the fifth transistor to turn off;

[0016] Sixth control signal, controlling the second transistor, the fourth transistor, and the sixth transistor to conduct, and controlling the first transistor, the third transistor, and the fifth transistor to turn off;

[0017] The seventh control signal controls the second transistor, the third transistor, and the fourth transistor to conduct, and controls the first transistor, the fifth transistor, and the sixth transistor to turn off;

[0018] The eighth control signal controls the third transistor and the fourth transistor to conduct, and controls the first transistor, the second transistor, the fifth transistor, and the sixth transistor to turn off;

[0019] The ninth control signal controls the third transistor, the fourth transistor, and the fifth transistor to conduct, and controls the first transistor, the second transistor, and the sixth transistor to turn off;

[0020] The tenth control signal controls the third transistor and the fifth transistor to conduct, and controls the first transistor, the second transistor, the fourth transistor, and the sixth transistor to turn off;

[0021] The eleventh control signal controls the first transistor, the third transistor, and the fifth transistor to conduct, and controls the second transistor, the fourth transistor, and the sixth transistor to turn off;

[0022] The twelfth control signal controls the first transistor and the fifth transistor to conduct, and controls the second transistor, the third transistor, the fourth transistor, and the sixth transistor to turn off.

[0023] In a possible implementation manner, the duty ratios of the first control signal, the third control signal, the fifth control signal, the seventh control signal, the ninth control signal, and the eleventh control signal are times that of the second control signal, the fourth control signal, the sixth control signal, the eighth control signal, the tenth control signal, and the twelfth control signal.

[0024] In a possible implementation manner, taking one end where the windings of the stator are connected as the center, when the first control signal, the third control signal, the fifth control signal, the seventh control signal, the ninth control signal, the eleventh control signal, the second control signal, the fourth control signal, the sixth control signal, the eighth control signal, the tenth control signal, and the twelfth control signal act, the space vector circle corresponding to this center is divided into 12 sectors. Each control signal corresponds to the edge of each sector, and the angle of each sector is 30°. Among them, the positioning module includes:

[0025] A first determination unit, configured to determine a first side where the bus current is the largest when the first control signal, the third control signal, the fifth control signal, the seventh control signal, the ninth control signal, and the eleventh control signal act respectively;

[0026] A second determination unit, configured to determine a second side where the bus current is the largest when the second control signal, the fourth control signal, the sixth control signal, the eighth control signal, the tenth control signal, and the twelfth control signal act respectively;

[0027] A positioning unit, configured to determine the position of the rotor according to the first side and the second side.

[0028] In a possible implementation manner, the positioning unit includes:

[0029] A first positioning sub-unit, configured to determine a first sector according to the first side, determine a second sector according to the second side, and determine a target sector where the rotor is located according to an overlapping area of the first sector and the second sector;

[0030] A second positioning sub-unit, configured to determine a sub-sector of the rotor in the target sector according to the larger one of the bus current corresponding to the first side and the bus current corresponding to the second side, where an angle of the sub-sector is 15°.

[0031] In a possible implementation manner, the driving module includes:

[0032] A timing control unit, configured to output a next set of control signals after a preset time period when outputting a set of control signals, so as to control conduction states of each transistor of the three-phase full-bridge inverter.

[0033] In a possible implementation manner, the three-phase full-bridge inverter includes a plurality of first input resistors, a plurality of second input resistors, and a plurality of input capacitors. Windings of the stator include a first winding, a second winding, and a third winding. Wherein, gates of each transistor of the three-phase full-bridge inverter are electrically connected to a second end of the first input resistor, a first end of the second input resistor, and a first end of the input capacitor. Sources of each transistor of the three-phase full-bridge inverter are electrically connected to a second end of the input capacitor and a second end of the second input resistor. A first end of the first input resistor is used for inputting a control signal,

[0034] Wherein, drains of the first transistor, the second transistor, and the third transistor are electrically connected, and sources of the fourth transistor, the fifth transistor, and the sixth transistor are electrically connected,

[0035] The source of the first transistor is electrically connected to the drain of the fourth transistor and the first end of the first winding. The source of the second transistor is electrically connected to the drain of the fifth transistor and the first end of the second winding. The source of the third transistor is electrically connected to the drain of the sixth transistor and the first end of the third winding.

[0036] The second ends of the first winding, the second winding, and the third winding are grounded.

[0037] In a possible implementation, the motor is a three-phase DC brushless motor.

[0038] According to one aspect of the present disclosure, a driving component is provided, and the driving component includes the motor rotor position positioning device described above.

[0039] According to one aspect of the present disclosure, a power tool is provided, and the power tool includes the driving component described above.

[0040] The motor rotor position positioning device in the embodiments of the present disclosure does not require a dedicated position sensor to be provided in the motor. By using the preset multi-group control signals output by the driving modules to control the three-phase full-bridge inverter to drive the electrodes, multiple bus currents of the motor under the control of the multi-group control signals are collected, and the position of the rotor is determined by using the multiple bus currents, so that the positioning of the rotor position can be realized. Compared with the related art, the positioning accuracy is improved, and the cost and space are saved.

[0041] According to the following detailed description of the exemplary embodiments with reference to the accompanying drawings, other features and aspects of the present disclosure will become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings included in the specification and constituting a part of the specification show the exemplary embodiments, features, and aspects of the present disclosure together with the specification, and are used to explain the principles of the present disclosure.

[0043] Figure 1 A schematic diagram of a motor rotor position positioning device according to an embodiment of the present disclosure is shown.

[0044] Figure 2 A schematic diagram of a motor space vector diagram according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0045] Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0046] In the description of the present disclosure, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present disclosure.

[0047] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present disclosure, "a plurality" means two or more unless otherwise specifically defined.

[0048] In the present disclosure, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0049] The term "exemplary" used herein means "serving as an example, embodiment, or illustration". Any embodiment described as "exemplary" herein need not be construed as superior to or better than other embodiments.

[0050] In addition, for a better illustration of the present disclosure, numerous specific details are given in the following detailed description. Those skilled in the art should understand that the present disclosure can be implemented without some specific details. In some instances, methods, means, elements, and circuits well known to those skilled in the art are not described in detail so as to highlight the gist of the present disclosure.

[0051] Please refer to Figure 1 , Figure 1 which shows a schematic diagram of a motor rotor position positioning device according to an embodiment of the present disclosure.

[0052] As Figure 1 shown, the device includes:

[0053] A three-phase motor 10, including a rotor and a stator;

[0054] Three-phase full-bridge inverter 20 includes a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5, and a sixth transistor Q6. The first transistor Q1 and the fourth transistor Q4 form a first bridge arm, the second transistor Q2 and the fifth transistor Q5 form a second bridge arm, and the third transistor Q3 and the sixth transistor Q6 form a third bridge arm. Wherein, one ends of the windings of the stator are electrically connected, and the other ends of the windings are respectively electrically connected between the first transistor Q1 and the fourth transistor Q4, between the second transistor Q2 and the fifth transistor Q5, and between the third transistor Q3 and the sixth transistor Q6;

[0055] Drive module 30 is electrically connected to the three-phase full-bridge inverter 20 and is configured to output a preset number of sets of control signals to control the conduction states of the transistors of the three-phase full-bridge inverter 20;

[0056] Positioning module 40 is electrically connected to the three-phase full-bridge inverter 20 and is configured to collect multiple bus currents of the motor under the control of multiple sets of control signals and determine the position of the rotor using the multiple bus currents.

[0057] The motor rotor position positioning device of the embodiments of the present disclosure does not require a dedicated position sensor to be provided in the motor. It uses the drive of each module to output a preset number of sets of control signals to control the three-phase full-bridge inverter to drive the electrodes, thereby collecting multiple bus currents of the motor under the control of multiple sets of control signals and determining the position of the rotor using the multiple bus currents. The rotor position can be positioned. Compared with the related art, the positioning accuracy is improved, and the cost and space are saved.

[0058] It should be noted that each module and unit of the embodiments of the present disclosure can be implemented by a hardware circuit or by combining a general hardware circuit with related existing logics.

[0059] In a possible implementation manner, the first transistor Q1, the second transistor Q2, the third transistor Q3, the fourth transistor Q4, the fifth transistor Q5, and the sixth transistor Q6 can be metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated gate bipolar transistors (IGBTs). Among them, the transistors can be implemented based on silicon carbide (SiC) and gallium nitride (GaN) to improve performance.

[0060] In a possible implementation manner, as Figure 1As shown, the three-phase full-bridge inverter 20 may further include a plurality of first input resistors, a plurality of second input resistors, and a plurality of input capacitors to filter the input signal. The windings of the stator include a first winding A, a second winding B, and a third winding C. Among them, the gates of the transistors of the three-phase full-bridge inverter 20 are electrically connected to the second ends of the first input resistors, the first ends of the second input resistors, and the first ends of the input capacitors. The sources of the transistors of the three-phase full-bridge inverter 20 are electrically connected to the second ends of the input capacitors and the second ends of the second input resistors. The first ends of the first input resistors are used to input control signals.

[0061] Among them, the drains of the first transistor Q1, the second transistor Q2, and the third transistor Q3 are electrically connected, and the sources of the fourth transistor Q4, the fifth transistor Q5, and the sixth transistor Q6 are electrically connected.

[0062] The source of the first transistor Q1 is electrically connected to the drain of the fourth transistor Q4 and the first end of the first winding. The source of the second transistor Q2 is electrically connected to the drain of the fifth transistor Q5 and the first end of the second winding. The source of the third transistor Q3 is electrically connected to the drain of the sixth transistor Q6 and the first end of the third winding.

[0063] The second ends of the first winding A, the second winding B, and the third winding C are grounded.

[0064] In one example, as Figure 1 shown, the first input resistors may include a first resistor R1, a third resistor R3, a fifth resistor R5, a seventh resistor R7, a ninth resistor R9, and an eleventh resistor R11. The second input resistors may include a second resistor R2, a fourth resistor R4, a sixth resistor R6, an eighth resistor R8, a tenth resistor R10, and a twelfth resistor R12. The input capacitors may include a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6.

[0065] In one example, the three-phase full-bridge inverter 20 may further include a plurality of freewheeling diodes, which are arranged between the sources and drains of the respective transistors and are used to provide a freewheeling path when the transistors are turned off to prevent the transistors from being damaged.

[0066] In one possible implementation, the motor is a three-phase DC brushless motor.

[0067] In one example, embodiments of the present disclosure implement the Y-connection (or star connection) of a three-phase motor by electrically connecting one ends of the windings of the stator, and electrically connecting the other ends of the windings between the first transistor Q1 and the fourth transistor Q4, between the second transistor Q2 and the fifth transistor Q5, and between the third transistor Q3 and the sixth transistor Q6 respectively.

[0068] In one example, as Figure 1 shown, a three-phase motor may include a first winding A, a second winding B, and a third winding C. One end of the first winding A is electrically connected between the first transistor Q1 and the fourth transistor Q4, one end of the second winding B is electrically connected between the second transistor Q2 and the fifth transistor Q5, and one end of the third winding C is electrically connected between the third transistor Q3 and the sixth transistor Q6.

[0069] Please refer to Figure 2 , Figure 2 which shows a schematic diagram of the motor space vector diagram according to an embodiment of the present disclosure.

[0070] In one example, as Figure 2 shown, the point where the other ends of the first winding A, the second winding B, and the third winding C are connected is point O. Figure 2 In the vector diagram shown, sides OA, OB, and OC are the three-phase vector positions of the motor, and there is an electrical angle difference of 120° between each of them.

[0071] Table 1

[0072]

[0073] Table 1 shows examples of control signals. Among them, "upper" represents the upper transistor of the bridge arm, and "lower" represents the lower transistor of the bridge arm. Exemplarily, taking the first control signal S1 as an example, "A upper" means the upper transistor of the first bridge arm corresponding to the first winding A (the first transistor Q1 is turned on), and "BC lower" means the lower transistors of the second bridge arm corresponding to the second winding B (the fifth transistor Q5) and the third bridge arm corresponding to the third winding C (the sixth transistor Q6) are turned on, and the remaining transistors not shown are turned off.

[0074] In a possible implementation manner, as shown in Table 1, the preset multiple groups of control signals may include:

[0075] The first control signal S1 controls the first transistor Q1, the fifth transistor Q5, and the sixth transistor Q6 to be turned on, and controls the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 to be turned off;

[0076] The second control signal S2 controls the first transistor Q1 and the sixth transistor Q6 to conduct, and controls the second transistor Q2, the third transistor Q3, the fourth transistor Q4, and the fifth transistor Q5 to turn off;

[0077] The third control signal S3 controls the first transistor Q1, the second transistor Q2, and the sixth transistor Q6 to conduct, and controls the third transistor Q3, the fourth transistor Q4, and the fifth transistor Q5 to turn off;

[0078] The fourth control signal S4 controls the second transistor Q2 and the sixth transistor Q6 to conduct, and controls the first transistor Q1, the third transistor Q3, the fourth transistor Q4, and the fifth transistor Q5 to turn off;

[0079] The fifth control signal S5 controls the second transistor Q2, the fourth transistor Q4, and the sixth transistor Q6 to conduct, and controls the first transistor Q1, the third transistor Q3, and the fifth transistor Q5 to turn off;

[0080] The sixth control signal S6 controls the second transistor Q2, the fourth transistor Q4, and the sixth transistor Q6 to conduct, and controls the first transistor Q1, the third transistor Q3, and the fifth transistor Q5 to turn off;

[0081] The seventh control signal S7 controls the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 to conduct, and controls the first transistor Q1, the fifth transistor Q5, and the sixth transistor Q6 to turn off;

[0082] The eighth control signal S8 controls the third transistor Q3 and the fourth transistor Q4 to conduct, and controls the first transistor Q1, the second transistor Q2, the fifth transistor Q5, and the sixth transistor Q6 to turn off;

[0083] The ninth control signal S9 controls the third transistor Q3, the fourth transistor Q4, and the fifth transistor Q5 to conduct, and controls the first transistor Q1, the second transistor Q2, and the sixth transistor Q6 to turn off;

[0084] The tenth control signal S10 controls the third transistor Q3 and the fifth transistor Q5 to conduct, and controls the first transistor Q1, the second transistor Q2, the fourth transistor Q4, and the sixth transistor Q6 to turn off;

[0085] The eleventh control signal S11 controls the first transistor Q1, the third transistor Q3, and the fifth transistor Q5 to conduct, and controls the second transistor Q2, the fourth transistor Q4, and the sixth transistor Q6 to turn off;

[0086] The twelfth control signal S12 controls the first transistor Q1 and the fifth transistor Q5 to conduct, and controls the second transistor Q2, the third transistor Q3, the fourth transistor Q4, and the sixth transistor Q6 to turn off.

[0087] In a possible implementation, as Figure 2 shown, one end where the windings of the stator are connected is used as the center O. When the first control signal S1, the third control signal S3, the fifth control signal S5, the seventh control signal S7, the ninth control signal S9, the eleventh control signal S11, the second control signal S2, the fourth control signal S4, the sixth control signal S6, the eighth control signal S8, the tenth control signal S10, and the twelfth control signal S12 act, the space vector diagram corresponding to this center is divided into 12 sectors. Each control signal corresponds to the side of each sector, and the angle of each sector is 30°.

[0088] In an example, as shown in Table 1 and Figure 2 shown, the first control signal S1, the third control signal S3, the fifth control signal S5, the seventh control signal S7, the ninth control signal S9, the eleventh control signal S11, the second control signal S2, the fourth control signal S4, the sixth control signal S6, the eighth control signal S8, the tenth control signal S10, and the twelfth control signal S12 respectively correspond to the sides OA, OZ, OB, OX, OC, OY, OD, OE, OF, OG, OH, and OK.

[0089] The above 12 groups of control signals, when controlling the states of the transistors of the three-phase full-bridge inverter and controlling the operation of the motor, divide the 360° electrical angle of the motor space vector diagram into 30°. Through such a control method, the positioning accuracy of the rotor can be controlled within 30°. Compared with the related art that can only provide a positioning accuracy of 60°, the embodiments of the present disclosure have the characteristics of high-precision positioning and do not require a position sensor.

[0090] It should be noted that although Figure 2 the shown motor space vector diagram is a regular hexagon, the embodiments of the present disclosure are not limited thereto. In other examples, the motor space vector diagram can also be circular, elliptical, etc. In this regard, the embodiments of the present disclosure do not make any limitations.

[0091] In a possible implementation, the duty cycles of the first control signal S1, the third control signal S3, the fifth control signal S5, the seventh control signal S7, the ninth control signal S9, and the eleventh control signal S11 are times that of the second control signal S2, the fourth control signal S4, the sixth control signal S6, the eighth control signal S8, the tenth control signal S10, and the twelfth control signal S12.

[0092] In an example, under the control of the first control signal S1, the third control signal S3, the fifth control signal S5, the seventh control signal S7, the ninth control signal S9, and the eleventh control signal S11, current passes through all three phases of the motor (which can be called the three-three conduction mode or the three-phase conduction mode), while under the control of the second control signal S2, the fourth control signal S4, the sixth control signal S6, the eighth control signal S8, the tenth control signal S10, and the twelfth control signal S12, current passes through only two phases of the motor (which can be called the two-two conduction mode or the two-phase conduction mode). Among them, the voltage utilization rate in the three-phase conduction mode is times that in the two-phase conduction mode. Therefore, in order to make the voltage injection consistent for the above twelve control modes to improve stability and reliability, the embodiments of the present disclosure make the duty cycles of the first control signal S1, the third control signal S3, the fifth control signal S5, the seventh control signal S7, the ninth control signal S9, and the eleventh control signal S11 times that of the second control signal S2, the fourth control signal S4, the sixth control signal S6, the eighth control signal S8, the tenth control signal S10, and the twelfth control signal S12.

[0093] In a possible implementation manner, the driving module 30 can be implemented by a hardware circuit or by using a general hardware circuit. For example, it can include a gate driver. The embodiments of the present disclosure do not limit the specific implementation manner of the gate driver, and those skilled in the art can implement it using the gate driver in related technologies.

[0094] In a possible implementation, the driving module 30 may include:

[0095] A timing control unit, configured to output the next set of control signals after a preset time interval after outputting a set of control signals, so as to control the on-off states of the transistors of the three-phase full-bridge inverter 20.

[0096] The timing control unit can be implemented by a hardware circuit. For example, it can include a timing controller, and the timing controller can be implemented using related technologies. In this regard, the embodiments of the present disclosure do not make any limitations.

[0097] By the timing control unit outputting a set of control signals and then outputting the next set of control signals after a preset time interval to control the conduction states of the transistors of the three-phase full-bridge inverter 20, the embodiments of the present disclosure can make the motor control more stable and obtain a more accurate positioning result.

[0098] The embodiments of the present disclosure do not limit the size of the preset time interval, and those skilled in the art can set it according to needs.

[0099] In a possible implementation manner, the positioning module 40 may include:

[0100] A first determination unit, configured to determine the first side where the bus current is the largest when the first control signal S1, the third control signal S3, the fifth control signal S5, the seventh control signal S7, the ninth control signal S9, and the eleventh control signal S11 act respectively;

[0101] A second determination unit, configured to determine the second side where the bus current is the largest when the second control signal S2, the fourth control signal S4, the sixth control signal S6, the eighth control signal S8, the tenth control signal S10, and the twelfth control signal S12 act respectively;

[0102] A positioning unit, configured to determine the position of the rotor according to the first side and the second side.

[0103] The positioning module can be implemented by a hardware circuit. For example, it can be implemented using a dedicated hardware circuit and a general hardware circuit. The general hardware circuit can include, for example, a microprocessor MCU, a central processing unit CPU, etc. When implementing the positioning module using the general hardware circuit, it can be combined with control instructions in related technologies. The present disclosure does not make any limitations in this regard.

[0104] In an example, the positioning module may include a current sampler (such as sampling using a resistor) to sample the bus current. For example, the current sampler may include at least one sampling resistor connected to the inverter to collect the bus current of the motor. The embodiments of the present disclosure do not limit the number of sampling resistors, and those skilled in the art can determine the number according to the power.

[0105] In an example, the first determination unit and the second determination unit may include several comparators to implement current comparison.

[0106] In the embodiments of the present disclosure, by determining the first side where the bus current is the largest when the first control signal S1, the third control signal S3, the fifth control signal S5, the seventh control signal S7, the ninth control signal S9, and the eleventh control signal S11 act respectively, and determining the second side where the bus current is the largest when the second control signal S2, the fourth control signal S4, the sixth control signal S6, the eighth control signal S8, the tenth control signal S10, and the twelfth control signal S12 act respectively, the sector where the rotor is located in the space vector diagram can be determined, thereby achieving preliminary positioning.

[0107] In a possible implementation manner, the positioning unit may include:

[0108] A first positioning sub-unit, configured to determine a first sector according to the first side, determine a second sector according to the second side, and determine the target sector where the rotor is located according to the overlapping area of the first sector and the second sector.

[0109] Table 2 shows the first side, the second side, the corresponding first sector, and the second sector determined according to each control signal.

[0110] Table 2

[0111]

[0112] Among them, by way of example, assuming that the determined first side is OA, the first sector corresponding to the first side is the ODAK sector, assuming that the second side is OD, the second sector is the OZDA sector, and the overlapping area of the ODAK sector and the OZDA sector is the ODA sector (target sector). In this way, the position where the rotor is located can be determined in the ODA sector, and the angle of the ODA sector is 30°.

[0113] In a possible implementation manner, the positioning unit may include:

[0114] A second positioning sub-unit, configured to determine the sub-sector of the rotor in the target sector according to the maximum of the bus current corresponding to the first side and the bus current corresponding to the second side, where the angle of the sub-sector is 15°.

[0115] In one example, assuming that the determined target sector is the ODA sector, the embodiments of the present disclosure can further determine the sub-sector of the rotor in the target sector according to the maximum of the busbar current corresponding to the first side and the busbar current corresponding to the second side. Assuming that the current corresponding to side OA is greater than the current corresponding to side OD, it can be determined that the position of the rotor is closer to side OA, that is, in the OPA sector (15°); conversely, if the current corresponding to side OD is greater than the current corresponding to side OA, it can be determined that the position of the rotor is closer to side OD, that is, the ODP sector (15°).

[0116] Through the above device, the embodiments of the present disclosure can achieve precise positioning of the rotor, and do not require a position sensor, saving costs and the space of the motor, and improving the applicability of heavy-load starting.

[0117] The embodiments of the present disclosure have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other ordinary skill in the art in the technical field to understand the embodiments disclosed herein.

Claims

1. A device for positioning the rotor position of a motor, characterized in that, the device includes: a three-phase motor, including a rotor and a stator; a three-phase full-bridge inverter, including a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor. The first transistor and the fourth transistor form a first bridge arm, the second transistor and the fifth transistor form a second bridge arm, and the third transistor and the sixth transistor form a third bridge arm. Wherein, one end of each winding of the stator is electrically connected, and the other end of each winding is respectively electrically connected between the first transistor and the fourth transistor, between the second transistor and the fifth transistor, and between the third transistor and the sixth transistor; a driving module, electrically connected to the three-phase full-bridge inverter, for outputting a preset set of control signals to control the on-off states of the transistors of the three-phase full-bridge inverter; a positioning module, electrically connected to the three-phase full-bridge inverter, for collecting multiple bus currents of the motor under the control of a set of control signals and determining the position of the rotor using the multiple bus currents, the preset set of control signals includes at least one of the following: a first control signal, controlling the first transistor, the fifth transistor, and the sixth transistor to conduct, and controlling the second transistor, the third transistor, and the fourth transistor to turn off; a second control signal, controlling the first transistor and the sixth transistor to conduct, and controlling the second transistor, the third transistor, the fourth transistor, and the fifth transistor to turn off; a third control signal, controlling the first transistor, the second transistor, and the sixth transistor to conduct, and controlling the third transistor, the fourth transistor, and the fifth transistor to turn off; a fourth control signal, controlling the second transistor and the sixth transistor to conduct, and controlling the first transistor, the third transistor, the fourth transistor, and the fifth transistor to turn off; a fifth control signal, controlling the second transistor, the fourth transistor, and the sixth transistor to conduct, and controlling the first transistor, the third transistor, and the fifth transistor to turn off; a sixth control signal, controlling the second transistor, the fourth transistor, and the sixth transistor to conduct, and controlling the first transistor, the third transistor, and the fifth transistor to turn off; a seventh control signal, controlling the second transistor, the third transistor, and the fourth transistor to conduct, and controlling the first transistor, the fifth transistor, and the sixth transistor to turn off; an eighth control signal, controlling the third transistor and the fourth transistor to conduct, and controlling the first transistor, the second transistor, the fifth transistor, and the sixth transistor to turn off; a ninth control signal, controlling the third transistor, the fourth transistor, and the fifth transistor to conduct, and controlling the first transistor, the second transistor, and the sixth transistor to turn off; The tenth control signal controls the third transistor and the fifth transistor to conduct, and controls the first transistor, the second transistor, the fourth transistor, and the sixth transistor to turn off; The eleventh control signal controls the first transistor, the third transistor, and the fifth transistor to conduct, and controls the second transistor, the fourth transistor, and the sixth transistor to turn off; The twelfth control signal controls the first transistor and the fifth transistor to conduct, and controls the second transistor, the third transistor, the fourth transistor, and the sixth transistor to turn off. One end of each winding of the stator is connected as the center of the circle. When the first control signal, the third control signal, the fifth control signal, the seventh control signal, the ninth control signal, the eleventh control signal, the second control signal, the fourth control signal, the sixth control signal, the eighth control signal, the tenth control signal, and the twelfth control signal act, the space vector circle corresponding to this center of the circle is divided into 12 sectors. Each control signal corresponds to the side of each sector, and the angle of each sector is 30°. Among them, the positioning module includes: A first determination unit for determining the first side where the bus current is the largest when the first control signal, the third control signal, the fifth control signal, the seventh control signal, the ninth control signal, and the eleventh control signal act respectively; A second determination unit for determining the second side where the bus current is the largest when the second control signal, the fourth control signal, the sixth control signal, the eighth control signal, the tenth control signal, and the twelfth control signal act respectively; A positioning unit for determining the position of the rotor according to the first side and the second side. The positioning unit includes: a first positioning sub-unit for determining a first sector according to the first side, determining a second sector according to the second side, and determining the target sector where the rotor is located according to the overlapping area of the first sector and the second sector; a second positioning sub-unit for determining the sub-sector of the rotor in the target sector according to the larger of the bus current corresponding to the first side and the bus current corresponding to the second side, where the angle of the sub-sector is 15°.

2. The device according to claim 1, characterized in that The duty cycles of the first control signal, the third control signal, the fifth control signal, the seventh control signal, the ninth control signal, and the eleventh control signal are times that of the second control signal, the fourth control signal, the sixth control signal, the eighth control signal, the tenth control signal, and the twelfth control signal.

3. The device according to claim 1, characterized in that The drive module includes: A timing control unit for outputting the next set of control signals after an interval of a preset time period when outputting a set of control signals to control the on-off states of the transistors of the three-phase full-bridge inverter.

4. The device according to claim 1, characterized in that The three-phase full-bridge inverter includes a plurality of first input resistors, a plurality of second input resistors, and a plurality of input capacitors. The windings of the stator include a first winding, a second winding, and a third winding. Among them, the gates of the transistors of the three-phase full-bridge inverter are electrically connected to the second ends of the first input resistors, the first ends of the second input resistors, and the first ends of the input capacitors. The sources of the transistors of the three-phase full-bridge inverter are electrically connected to the second ends of the input capacitors and the second ends of the second input resistors. The first ends of the first input resistors are used to input control signals. Among them, the drains of the first transistor, the second transistor, and the third transistor are electrically connected, and the sources of the fourth transistor, the fifth transistor, and the sixth transistor are electrically connected. The source of the first transistor is electrically connected to the drain of the fourth transistor and the first end of the first winding. The source of the second transistor is electrically connected to the drain of the fifth transistor and the first end of the second winding. The source of the third transistor is electrically connected to the drain of the sixth transistor and the first end of the third winding. The second ends of the first winding, the second winding, and the third winding are grounded.

5. The device according to claim 1, wherein, the motor is a three-phase DC brushless motor.

6. A drive assembly, wherein, the drive assembly includes the motor rotor position positioning device according to any one of claims 1-5.

7. A power tool, wherein, the power tool includes the drive assembly according to claim 6.

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