Double-resistor motor control circuit and motor control system

Abstract

The invention provides a dual-resistor motor control circuit and a motor control system. The dual-resistor motor control circuit comprises a main controller, a first phase current sampling circuit, a second phase current sampling circuit and a third phase current sampling circuit, and each of the first phase current sampling circuit, the second phase current sampling circuit and the third phase current sampling circuit comprises N power conversion units, each power conversion unit is electrically connected with the same phase winding of different motors, a first sampling resistor is arranged in the first phase current sampling circuit and used for collecting first phase current of the N motors, and a second sampling resistor is arranged in the second phase current sampling circuit and used for collecting second phase current of the N motors. The main controller is used for obtaining a corresponding third phase current based on the first phase current and the second phase current of each motor, and controlling the running state of each motor based on the first phase current, the second phase current and the third phase current; wherein N is a positive integer greater than 1. The dual-resistor sampling can reduce the cost.

Description

Technical Field

[0001] The present disclosure relates to the field of motors, and in particular to a dual-resistance motor control circuit and a motor control system. Background Art

[0002] With economic development and social progress, range hoods, refrigerators, and air conditioners have gradually become essential household appliances in people's daily lives. Fans using variable frequency drives typically use permanent magnet synchronous motors. With technological advancements, a single household appliance may incorporate two permanent magnet synchronous motors. These two permanent magnet synchronous motors are controlled by a single microcontroller (MCU). In real-world scenarios, two permanent magnet synchronous motors often operate simultaneously. However, MCUs often lack analog-to-digital (A / D) sampling units. Furthermore, sampling resistors are expensive and take up circuit board space when operating at high power.

[0003] Using Hall sensors to sample the motor phase current is simple but expensive. To reduce costs, three resistors are connected in series in the lower arm circuit of the three-phase inverter for sampling. However, if two permanent magnet synchronous motors are running at the same time and the three resistors are shared for sampling, the sampling points of the two motor phase currents will overlap, making sampling impossible.

[0004] Therefore, when driving two permanent magnet synchronous motors simultaneously, the generation method and sampling strategy of PWM (pulse width modulation) of two groups of six-way inverters are technical problems that the industry needs to solve. Summary of the Invention

[0005] The technical problem to be solved by the present disclosure is to overcome the defects of the prior art in that the motor phase current sampling cost is high and multiple motor phase currents cannot be sampled simultaneously, and to provide a dual-resistance motor control circuit and a motor control system.

[0006] The present disclosure solves the above technical problems through the following technical solutions:

[0007] According to a first aspect of the present disclosure, there is provided a dual-resistance motor control circuit, the dual-resistance motor control circuit comprising a main controller, a first-phase current sampling circuit, a second-phase current sampling circuit, and a third-phase current sampling circuit;

[0008] The first phase current sampling circuit, the second phase current sampling circuit, and the third phase current sampling circuit each include N power conversion units, a first end of each power conversion unit is electrically connected to the main controller, and a second end of each power conversion unit is electrically connected to the same phase winding of different motors;

[0009] Each of the power conversion units includes a drive circuit, an upper bridge arm circuit and a lower bridge arm circuit electrically connected to the drive circuit, the connection point between the upper bridge arm circuit and the lower bridge arm circuit is the second end, and one second end corresponds to one phase winding of the motor;

[0010] The lower bridge arm circuit of each power conversion unit in the first phase current sampling circuit and the main controller are electrically connected to the third end of the first sampling resistor, and the fourth end of the first sampling resistor is grounded;

[0011] The lower bridge arm circuit of each power conversion unit in the second phase current sampling circuit and the main controller are electrically connected to the fifth end of the second sampling resistor, and the sixth end of the second sampling resistor is grounded;

[0012] The first phase current sampling circuit is used to collect the first phase currents of the N motors based on a sampling instruction, and transmit the first phase currents to the main controller;

[0013] The second-phase current sampling circuit is used to collect the second-phase currents of the N motors based on the sampling instruction, and transmit the second-phase currents to the main controller;

[0014] The main controller is used to obtain a corresponding third-phase current based on the first-phase current and the second-phase current of each motor, and control the operating state of each motor based on the first-phase current, the second-phase current and the third-phase current;

[0015] Wherein, N is a positive integer greater than 1.

[0016] Preferably, the first phase current sampling circuit further includes a first current amplifying unit, and the second phase current sampling circuit further includes a second current amplifying unit;

[0017] The third end of the first sampling resistor is electrically connected to the main controller via the first current amplifying unit;

[0018] The first current amplifying unit is used to amplify the input first phase current and transmit the amplified first phase current to the main controller;

[0019] The fifth end of the second sampling resistor is electrically connected to the main controller via the second current amplifying unit;

[0020] The second current amplifying unit is used to amplify the input second phase current and transmit the amplified second phase current to the main controller.

[0021] Preferably, when N=2;

[0022] The two power conversion units in the first phase current sampling circuit are respectively a first power conversion unit and a second power conversion unit;

[0023] The two power conversion units in the second phase current sampling circuit are respectively a third power conversion unit and a fourth power conversion unit;

[0024] The main controller is used to control the closed state of the first power conversion unit and the second power conversion unit to collect the first phase current of the first motor or the second motor;

[0025] The main controller is further configured to control the closed state of the third power conversion unit and the fourth power conversion unit to collect the second phase current of the first motor or the second motor.

[0026] Preferably, the main controller includes a signal generator;

[0027] The signal generator is used to generate a PWM wave to control each of the motors based on the instructions of the main controller, and transmit the PWM wave to the corresponding motor via the first phase current sampling circuit, the second phase current sampling circuit and the third phase current sampling circuit to control the operating state of each of the motors.

[0028] Preferably, the main controller further comprises a timer, and the signal generator comprises a triangle wave generator;

[0029] The triangular wave generator is used to generate the PWM wave for controlling each of the motors;

[0030] The timer is used to measure the period of the PWM wave;

[0031] The main controller is used to determine the sampling moments of the first motor and the second motor based on the period of the PWM wave, and generate the sampling instruction at the sampling moments.

[0032] Preferably, the main controller is used to control the triangle wave generator to generate a first PWM wave for controlling the first motor and a second PWM wave for controlling the second motor;

[0033] The first power conversion unit includes a first upper bridge arm circuit and a first lower bridge arm circuit;

[0034] The second power conversion unit includes a second upper bridge arm circuit and a second lower bridge arm circuit;

[0035] The third power conversion unit includes a third upper bridge arm circuit and a third lower bridge arm circuit;

[0036] The fourth power conversion unit includes a fourth upper bridge arm circuit and a fourth lower bridge arm circuit;

[0037] The main controller is further configured to, at a first sampling moment, insert a first preset voltage vector into the first PWM wave, insert a second preset voltage vector into the second PWM wave, and control the first upper bridge arm circuit, the second lower bridge arm circuit, the third upper bridge arm circuit, and the fourth lower bridge arm circuit to be disconnected, and the first lower bridge arm circuit, the second upper bridge arm circuit, the third lower bridge arm circuit, and the fourth upper bridge arm circuit to be closed, so as to collect the first phase current and the second phase current of the first motor;

[0038] The first sampling moment is an overflow moment or an underflow moment of the first PWM wave.

[0039] Preferably, the main controller is further configured to, at a second sampling moment, insert a third preset voltage vector into the first PWM wave, insert a fourth preset voltage vector into the second PWM wave, and control the first lower bridge arm circuit, the second upper bridge arm circuit, the third lower bridge arm circuit, and the fourth upper bridge arm circuit to be disconnected, and the first upper bridge arm circuit, the second lower bridge arm circuit, the third upper bridge arm circuit, and the fourth lower bridge arm circuit to be closed, so as to collect the first phase current and the second phase current of the second motor;

[0040] When the first sampling moment is the overflow moment, the second sampling moment is the underflow moment of the second PWM wave; when the first sampling moment is the underflow moment, the second sampling moment is the overflow moment of the second PWM wave.

[0041] Preferably, the duration of the preset voltage vector is equal to the duration of the sampling window;

[0042] and / or,

[0043] The main controller is configured to obtain the corresponding third-phase current based on the following formula:

[0044]

[0045] in, is the third phase current, is the first phase current, is the second phase current.

[0046] Preferably, the PWM wave generated by the triangular wave generator to control each of the motors satisfies the following conditions:

[0047]

[0048] Among them, Dmax is the maximum duty cycle corresponding to the PWM wave signal, T pwm is the signal period of the PWM wave, and T is the duration of the sampling window.

[0049] According to a second aspect of the present disclosure, a motor control system is provided, which includes N motors and the dual-resistance motor control circuit according to the first aspect of the present disclosure.

[0050] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0051] The positive progress of the present disclosure lies in: by short-circuiting the lower bridge arm circuits of N power conversion units and connecting sampling resistors in series to ground, a shared sampling resistor is used to collect the single-phase current corresponding to N permanent magnet synchronous motors, thereby reducing the number of sampling resistors and lowering costs. A single microcontroller is used to simultaneously control two motors, sampling the phase currents of both motors within a single PWM cycle and controlling both inverters simultaneously, achieving high real-time performance. Furthermore, by sharing a triangular wave generator, the microcontroller only needs a single timer interrupt to achieve simultaneous control of the two motors, reducing the requirements for the single-chip microcomputer. Furthermore, a low-cost dual-resistor sampling solution and a shared sampling resistor are used, further reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a first circuit diagram of the dual-resistance motor control circuit of Example 1;

[0053] Figure 2 The second circuit diagram of the dual-resistance motor control circuit of Example 1;

[0054] Figure 3 The third circuit diagram of the dual-resistance motor control circuit of Example 1;

[0055] Figure 4 4 is a fourth circuit diagram of the dual-resistance motor control circuit of Example 1;

[0056] Figure 5 5 is a fifth circuit diagram of the dual-resistance motor control circuit of Example 1;

[0057] Figure 6 4 is a sixth circuit diagram of the dual-resistance motor control circuit of Example 1;

[0058] Figure 7 The SVPWM (space vector pulse width modulation) output strategy and phase current sampling timing diagram of the power conversion unit of Example 1;

[0059] Figure 8 This is a diagram of the closed state of the power conversion unit at the first sampling moment of Example 1;

[0060] Figure 9 This is a diagram of the closed state of the power conversion unit at the second sampling moment of Example 1;

[0061] Figure 10 Schematic diagram of voltage vectors and sectors in Example 1;

[0062] Figure 11 This is a control flow chart of the main controller in Example 1;

[0063] Figure 12 This is the circuit diagram of the motor control system of Example 2. DETAILED DESCRIPTION

[0064] The present disclosure is further illustrated below by way of examples, but the present disclosure is not limited to the scope of the examples.

[0065] Example 1

[0066] In a specific embodiment of the present disclosure, a dual-resistance motor control circuit 100 is provided. Figure 1-2 As shown, the dual-resistance motor control circuit 100 includes a main controller 1, a first-phase current sampling circuit 2, a second-phase current sampling circuit 3, and a third-phase current sampling circuit 4;

[0067] The first phase current sampling circuit 2, the second phase current sampling circuit 3 and the third phase current sampling circuit 4 each include N power conversion units 11, a first end 111 of each power conversion unit 11 is electrically connected to the main controller 1, and a second end 112 of each power conversion unit 11 is electrically connected to the same phase winding of different motors;

[0068] Each power conversion unit 11 includes a drive circuit 113, an upper bridge arm circuit 114 and a lower bridge arm circuit 115 electrically connected to the drive circuit 113, and the connection point between the upper bridge arm circuit 114 and the lower bridge arm circuit 115 is a second end 112, and each second end 112 corresponds to a phase winding of a motor;

[0069] The lower bridge arm circuit 115 of each power conversion unit 11 in the first phase current sampling circuit 2 and the main controller 1 are electrically connected to the third end of the first sampling resistor 21, and the fourth end of the first sampling resistor 21 is grounded;

[0070] The lower bridge arm circuit 115 of each power conversion unit 11 in the second phase current sampling circuit 3 and the main controller 1 are electrically connected to the fifth end of the second sampling resistor 31, and the sixth end of the second sampling resistor 31 is grounded;

[0071] The first phase current sampling circuit 2 is used to collect the first phase currents of the N motors based on the sampling instruction and transmit the first phase currents to the main controller 1;

[0072] The second phase current sampling circuit 3 is used to collect the second phase currents of the N motors based on the sampling instruction and transmit the second phase currents to the main controller 1;

[0073] The main controller 1 is used to obtain the corresponding third-phase current based on the first-phase current and the second-phase current of each motor, and control the operating state of each motor based on the first-phase current, the second-phase current and the third-phase current;

[0074] Wherein, N is a positive integer greater than 1.

[0075] Specifically, in the dual-resistance motor control circuit 100, the first phase current sampling circuit 2, the second phase current sampling circuit 3 and the third phase current sampling circuit 4 are all electrically connected to the first phase winding, the second phase winding and the third phase winding of the N motors through N power conversion units 11, that is, the second ends 112 of the N power conversion units 11 in the first phase current sampling circuit 2 are electrically connected to the first phase winding of the N motors, the second ends 112 of the N power conversion units 11 in the second phase current sampling circuit 3 are electrically connected to the second phase winding of the N motors, and the second ends 112 of the N power conversion units 11 in the third phase current sampling circuit 4 are electrically connected to the third phase winding of the N motors, and each power conversion unit 11 is connected to the main controller 1, wherein the first phase winding, the second phase winding and the third phase winding correspond to the U phase, V phase and W phase of the motor, respectively.

[0076] For the first phase current sampling circuit 2 and the second phase current sampling circuit 3, when the driving circuit 113 receives the sampling instruction from the main controller, the first phase current and the second phase current of the N motors are collected by controlling the closed state of the upper bridge arm circuit 114 and the lower bridge arm circuit 115 in the N power conversion units 11 of the first phase current sampling circuit 2 and the second phase current sampling circuit 3.

[0077] Among them, such as Figure 3 As shown, the upper bridge arm circuit 114 and the lower bridge arm circuit 115 of each power conversion unit 11 can be IGBTs (insulated gate bipolar transistors), the emitters of the lower bridge arm circuits 115 of the N power conversion units 11 are short-circuited, the drive circuit 113 can be a pre-driver chip, and the power conversion unit 11 uses the PWM complementary signal of the main controller 1 as input, the pre-driver chip and the upper and lower power switch IGBTs as inverters, and the common end of the upper and lower power switch IGBTs as output, and is connected to a phase winding of the motor.

[0078] Since the first-phase current sampling circuit 2 and the second-phase current sampling circuit 3 are provided with sampling resistors, sampling of the phase current can be achieved. Therefore, the two-phase current in each motor can be collected through the first-phase current sampling circuit 2 and the second-phase current sampling circuit 3. After obtaining the two-phase current in each motor, the main controller 1 can reconstruct the third-phase current based on the principle that the vector sum current value of the three-phase current addition is zero, and then perform motor drive control calculations based on the U-phase current, V-phase current and W-phase current of each motor to generate a PWM complementary signal, thereby controlling the operating state of each motor.

[0079] For example, the N power conversion units 11 in the first phase current sampling circuit 2 are respectively connected to the U-phase windings of the N motors to collect the U-phase currents of the N motors. The N power conversion units 11 in the second phase current sampling circuit 3 are respectively connected to the V-phase windings of the N motors to collect the V-phase currents of the N motors. The N power conversion units 11 in the third phase current sampling circuit 4 are respectively connected to the W-phase windings of the N motors, wherein each power conversion unit 11 is only connected to one phase winding of one motor. The main controller 1 collects the U-phase current and V-phase current corresponding to each motor through the first phase current sampling circuit 2 and the second phase current sampling circuit 3, reconstructs the corresponding W-phase current, performs drive control calculations for each motor, and thereby realizes control of the operating state of each motor.

[0080] The motor may be a permanent magnet synchronous motor.

[0081] It should be noted that Figure 2 and Figure 3 The circuit diagram of the first phase current sampling circuit 2 is taken as an example. After the emitters of the lower bridge arm circuits 115 of the N power conversion units 11 are short-circuited, the first sampling resistor 21 is also connected in series. The circuit diagrams of the second phase current sampling circuit 3 and the third phase current sampling circuit 4 are not shown, and can be combined with Figure 1 and Figure 2 Understand.

[0082] This specific embodiment short-circuits the lower bridge arm circuits of N power conversion units and connects sampling resistors in series to ground, thereby achieving the goal of collecting single-phase currents corresponding to N motors through only one sampling resistor. This reduces the number of sampling resistors, lowers costs, saves circuit board space, and achieves high-quality refined processes. Two sampling resistors are used to simultaneously sample the phase currents of N motors within one PWM cycle, and a main controller is used to simultaneously control the N motors. By simultaneously controlling N groups of inverters, high real-time performance is achieved.

[0083] In a specific embodiment, the first phase current sampling circuit 2 further includes a first current amplifying unit, and the second phase current sampling circuit 3 further includes a second current amplifying unit;

[0084] The third end of the first sampling resistor 21 is electrically connected to the main controller 1 via the first current amplifying unit;

[0085] The first current amplifying unit is used to amplify the input first phase current and transmit the amplified first phase current to the main controller 1;

[0086] The fifth end of the second sampling resistor 31 is electrically connected to the main controller 1 via the second current amplifying unit;

[0087] The second current amplifying unit is used to amplify the input second-phase current and transmit the amplified second-phase current to the main controller 1 .

[0088] Specifically, taking the first phase current sampling circuit 2 as an example, Figure 4 As shown, in order to ensure that the phase current received by the main controller is within the preset output current range and improve the signal-to-noise ratio of the current, the first phase current sampling circuit 2 is further provided with a first current amplifying unit 22 electrically connected to the first sampling resistor 21 and the main controller 1, respectively, to amplify the collected phase current and transmit the amplified phase current to the main controller. The second phase current sampling circuit 3 is similarly configured.

[0089] In one embodiment, Figure 5 As shown, when N=2;

[0090] The two power conversion units 11 in the first phase current sampling circuit 2 are respectively a first power conversion unit 211 and a second power conversion unit 212;

[0091] The two power conversion units 11 in the second phase current sampling circuit 3 are respectively a third power conversion unit 311 and a fourth power conversion unit 312;

[0092] The main controller 1 is used to control the closed state of the first power conversion unit 211 and the second power conversion unit 212 to collect the first phase current of the first motor or the second motor;

[0093] The main controller 1 is further configured to control the closed state of the third power conversion unit 311 and the fourth power conversion unit 312 to collect the second phase current of the first motor or the second motor.

[0094] Specifically, for dual-motor control (i.e., N=2), the first-phase current sampling circuit 2, the second-phase current sampling circuit 3, and the third-phase current sampling circuit 4 are electrically connected to the three-phase windings of the two motors, respectively. For example, the first power conversion unit 211 in the first-phase current sampling circuit 2 is electrically connected to the first-phase winding of the first motor, the second power conversion unit 212 is electrically connected to the first-phase winding of the second motor, the third power conversion unit 311 in the second-phase current sampling circuit 3 is electrically connected to the second-phase winding of the first motor, the fourth power conversion unit 312 is electrically connected to the second-phase winding of the second motor, and the two power conversion units in the third-phase current sampling circuit 4 are electrically connected to the third-phase windings of the first motor and the second motor, respectively.

[0095] When collecting the phase currents of the first motor and the second motor, the main controller 1 controls the closed state of the first power conversion unit 211, the second power conversion unit 212, the third power conversion unit 311, and the fourth power conversion unit 312 to collect the first phase current and the second phase current of the first motor and the second motor, and then reconstruct the third phase current based on the principle that the vector sum current value of the three-phase current is zero to obtain the three-phase current corresponding to the first motor and the second motor.

[0096] In one embodiment, the main controller 1 includes a signal generator;

[0097] The signal generator is used to generate PWM waves to control each motor based on the instructions of the main controller 1, and transmit them to the corresponding motor via the first phase current sampling circuit 2, the second phase current sampling circuit 3 and the third phase current sampling circuit 4 to control the operating status of each motor.

[0098] In one embodiment, the main controller 1 further includes a timer, and the signal generator includes a triangle wave generator;

[0099] The triangle wave generator is used to generate the PWM wave to control each motor;

[0100] The timer is used to measure the period of the PWM wave;

[0101] The main controller 1 is used to determine the sampling moments of the first motor and the second motor based on the period of the PWM wave, and to generate a sampling instruction at the sampling moment.

[0102] Specifically, the first-phase current sampling circuit 2, the second-phase current sampling circuit 3, and the third-phase current sampling circuit 4 use the same triangular carrier signal to generate a PWM wave. The timer determines the sampling time of the first motor and the second motor by measuring the period of the PWM wave generated by the triangular carrier signal, and generates a sampling instruction when the sampling time is reached to control the closed state of the first power conversion unit 211, the second power conversion unit 212, the third power conversion unit 311, and the fourth power conversion unit 312, thereby obtaining the three-phase current corresponding to the first motor and the second motor.

[0103] In this specific embodiment, by sharing the triangle wave generator, the main controller 1 only needs one timer interrupt to achieve simultaneous control of the two motors, which has low requirements for the single-chip microcomputer and adopts a low-cost dual-resistance sampling solution and shares the sampling resistor, further reducing the cost.

[0104] In a specific embodiment, the main controller 1 is used to control the triangle wave generator to generate a first PWM wave for controlling the first motor and a second PWM wave for controlling the second motor;

[0105] like Figure 6 As shown, the first power conversion unit 211 includes a first upper bridge arm circuit 2111 and a first lower bridge arm circuit 2112;

[0106] The second power conversion unit 212 includes a second upper bridge arm circuit 2121 and a second lower bridge arm circuit 2122;

[0107] The third power conversion unit 311 includes a third upper bridge arm circuit 3111 and a third lower bridge arm circuit 3112;

[0108] The fourth power conversion unit 312 includes a fourth upper bridge arm circuit 3121 and a fourth lower bridge arm circuit 3122;

[0109] The main controller 1 is further configured to insert a first preset voltage vector V into the first PWM wave at a first sampling moment. 00X , insert the second preset voltage vector V into the second PWM wave 11Y , and controlling the first upper bridge arm circuit 2111, the second lower bridge arm circuit 2122, the third upper bridge arm circuit 3111, and the fourth lower bridge arm circuit 3122 to be disconnected, and the first lower bridge arm circuit 2112, the second upper bridge arm circuit 2121, the third lower bridge arm circuit 3112, and the fourth upper bridge arm circuit 3121 to be closed, so as to collect the first phase current and the second phase current of the first motor;

[0110] The first sampling moment is an overflow moment or an underflow moment of the first PWM wave.

[0111] Specifically, the underflow moment (starting moment) or overflow moment (intermediate moment) of the triangular carrier signal wave can be used as the sampling moment of the phase current of the first motor, that is, the underflow moment or overflow moment of the triangular carrier signal is the first sampling moment.

[0112] At the first sampling moment, the main controller 1 inserts a first preset voltage vector V into the first PWM wave. 00X , insert the second preset voltage vector V into the second PWM wave 11Y , and controls the upper bridge arms of the first power conversion unit 211 and the third power conversion unit 311 electrically connected to the first phase winding and the second phase winding of the first motor to be disconnected, and the lower bridge arms to be closed, and controls the upper bridge arms of the second power conversion unit 212 and the fourth power conversion unit 312 electrically connected to the first phase winding and the second phase winding of the second motor to be closed, and the lower bridge arms to be disconnected, thereby realizing the collection of the first phase current and the second phase current of the first motor.

[0113] That is, if Figure 7-8 As shown, at the first sampling moment, by inserting the first preset voltage vector V into the first PWM wave 00X , insert the second preset voltage vector V into the second PWM wave 11Y , and control the first upper bridge arm circuit 2111 to disconnect, the first lower bridge arm circuit 2112 to close, the second upper bridge arm circuit 2121 to close, and the second lower bridge arm circuit 2122 to disconnect to collect the first phase current of the first motor; control the third upper bridge arm circuit 3111 to disconnect, the third lower bridge arm circuit 3112 to close, the fourth upper bridge arm circuit 3121 to close, and the fourth lower bridge arm circuit 3122 to disconnect to collect the second phase current of the first motor.

[0114] It should be noted that V 00X and V 11Y is the preset voltage vector, where V 00X Low level, V 11Y It is at a high level. When the first sampling moment arrives, a low-level voltage vector is inserted into the first PWM wave controlling the first motor to artificially construct a sampling moment to realize the phase current sampling of the first motor. At the same time, a high-level voltage vector is inserted into the second PWM wave controlling the second motor to avoid the second motor affecting the phase current sampling of the first motor, thereby ensuring the reliability and accuracy of the phase current sampling of the first motor.

[0115] In a specific embodiment, the main controller 1 is further configured to insert a third preset voltage vector V into the first PWM wave at the second sampling moment. 11X , insert the fourth preset voltage vector V into the second PWM wave 00Y, and controlling the first lower bridge arm circuit 2112, the second upper bridge arm circuit 2121, the third lower bridge arm circuit 3112, and the fourth upper bridge arm circuit 3121 to be disconnected, and the first upper bridge arm circuit 2111, the second lower bridge arm circuit 2122, the third upper bridge arm circuit 3111, and the fourth lower bridge arm circuit 3122 to be closed, so as to collect the first phase current and the second phase current of the second motor;

[0116] When the first sampling moment is an overflow moment, the second sampling moment is an underflow moment of the second PWM wave; when the first sampling moment is an underflow moment, the second sampling moment is an overflow moment of the second PWM wave.

[0117] Specifically, the underflow or overflow moment of the triangular carrier signal can be used as the sampling moment of the phase current of the second motor, that is, the underflow or overflow moment of the triangular carrier signal is the second sampling moment. If the first sampling moment is the underflow moment, the overflow moment can be used as the second sampling moment; conversely, if the first sampling moment is the overflow moment, the underflow moment can be used as the second sampling moment.

[0118] At the second sampling moment, the main controller 1 inserts a third preset voltage vector V into the first PWM wave. 11X , insert the fourth preset voltage vector V into the second PWM wave 00Y , and controls the upper bridge arms of the first power conversion unit 211 and the third power conversion unit 311 electrically connected to the first phase winding and the second phase winding of the first motor to be closed, and the lower bridge arms to be disconnected, and controls the upper bridge arms of the second power conversion unit 212 and the fourth power conversion unit 312 electrically connected to the first phase winding and the second phase winding of the second motor to be disconnected, and the lower bridge arms to be closed, thereby realizing the collection of the first phase current and the second phase current of the second motor.

[0119] That is, if Figure 7 and Figure 9 As shown, at the second sampling moment, by inserting the third preset voltage vector V into the first PWM wave 11X , insert the fourth preset voltage vector V into the second PWM wave 00Y , and control the first upper bridge arm circuit 2111 to close, the first lower bridge arm circuit 2112 to open, the second upper bridge arm circuit 2121 to open, and the second lower bridge arm circuit 2122 to close to collect the first phase current of the second motor; control the third upper bridge arm circuit 3111 to close, the third lower bridge arm circuit 3112 to open, the fourth upper bridge arm circuit 3121 to open, and the fourth lower bridge arm circuit 3122 to close to collect the second phase current of the second motor.

[0120] Where V 11X and V 00Y is the preset voltage vector, V 11X Low level, V00Y is high level.

[0121] This specific implementation utilizes a time-sharing insertion strategy for the voltage vector. By inserting a high level, the motor that is not being sampled does not affect the phase current sampling of the sampling motor, thereby sampling the phase currents of two motors within one PWM cycle. This avoids timing conflicts in phase current sampling when two permanent magnet synchronous motors operate simultaneously and share a dual-resistance sampling circuit.

[0122] In one embodiment, the duration of the preset voltage vector is equal to the duration of the sampling window;

[0123] Specifically, because the preset voltage vector is a manually constructed sampling moment, phase current sampling occurs within the duration of the preset voltage vector. That is, the duration of the preset voltage vector is equal to the sampling window duration. For example, the sampling window duration T∈[1,3]us, or T=2us. The specific sampling window duration setting can be adjusted as needed and is not specifically limited in this embodiment.

[0124] In a specific embodiment, the main controller 1 is configured to obtain the corresponding third-phase current based on the following formula:

[0125]

[0126] in, is the third phase current, is the first phase current, is the second phase current.

[0127] Specifically, such as Figure 10 As shown, the voltage space vector of the three-phase motor can usually be divided into 6 sectors. According to the principle that the vector sum of the three-phase currents is zero, after collecting the first-phase current and the second-phase current of the first motor, the voltage space vector of the three-phase motor can be divided into 6 sectors. The third phase current of the first motor is reconstructed and obtained. Similarly, the corresponding third phase current can be reconstructed based on the first phase current and the second phase current of the second motor.

[0128] In one embodiment, the PWM wave generated by the triangle wave generator to control each motor satisfies the following conditions:

[0129]

[0130] Among them, D max is the maximum duty cycle corresponding to the PWM wave signal, T pwm is the signal period of the PWM wave, and T is the sampling window length.

[0131] Specifically, since a preset voltage vector equal to the sampling window duration needs to be inserted into the PWM wave, it is necessary to adjust the maximum duty cycle of the PWM wave signal to reserve an insertion time for the inserted preset voltage vector, so as to realize the insertion of the preset voltage vector and perform phase current collection to ensure that the phase current sampling between the first motor and the second motor does not interfere with each other.

[0132] In a specific example, Figure 11 As shown, the underflow moment of the triangular carrier signal is used as the first sampling moment, and the overflow moment of the triangular carrier signal is used as the second sampling moment. The control process of the main controller 1 is as follows:

[0133] Step 1: The permanent magnet synchronous motor starts, and the first phase current sampling circuit 2, the second phase current sampling circuit 3 and the third phase current sampling circuit 4 use the same triangular carrier signal to generate SVPWM waves, and the two motors run;

[0134] Step 2: Determine whether the triangular carrier signal is at the underflow moment. If so, jump to step 3, otherwise jump to step 4;

[0135] Step 3: Insert the voltage vector V into the SVPWM wave corresponding to the first motor 00X , insert the voltage vector V into the SVPWM wave corresponding to the second motor 11Y , the insertion time is the sampling window time T, and the phase current of the first motor is collected;

[0136] Step 4: Determine whether the triangular carrier signal is at the overflow moment. If so, jump to step 5, otherwise return to step 2;

[0137] Step 5: Insert the voltage vector V into the SVPWM wave corresponding to the first motor 11X , insert the voltage vector V into the SVPWM wave corresponding to the second motor 00Y , the insertion time is the sampling window time T, and the phase current of the second motor is collected;

[0138] Step 6: By sampling the current, the U-phase current of the first motor and the second motor can be sampled. and V phase current Among them, the W phase current is

[0139] Select the corresponding power conversion unit, generate SVPWM wave, control the motor corresponding to the sampled current, and return to step 2; wherein, the maximum duty cycle D corresponding to the SVPWM modulated PWM signal max satisfy

[0140]

[0141] T pwmCorresponding to the period of the PWM signal, generally, T pwm ∈[50,250]us, or, T pwm =100us.

[0142] This embodiment short-circuits the lower bridge arm circuits of N power conversion units and connects sampling resistors in series to ground. This shared sampling resistor collects the single-phase current corresponding to N permanent magnet synchronous motors, reducing the number of sampling resistors and lowering costs. A single microcontroller simultaneously controls two motors, sampling both motor phase currents within a single PWM cycle and simultaneously controlling both inverters, achieving high real-time performance. Furthermore, by sharing a triangular wave generator, the microcontroller only requires a single timer interrupt to simultaneously control both motors, reducing requirements on the microcontroller. Furthermore, a low-cost dual-resistor sampling solution and shared sampling resistors further reduce costs.

[0143] Example 2

[0144] In a specific embodiment of the present disclosure, a motor control system is provided, such as Figure 12 As shown, the motor control system includes N motors 200 and the dual-resistance motor control circuit 100 of Example 1. The specific implementation principle can be found in Example 1, and the present disclosure will not elaborate on it here.

[0145] Among them, the motor control system can be used in various electrical appliances such as floor scrubbers, dishwashers with drainage pumps, refrigerators with dual compressors, and range hoods with dual fan systems.

[0146] This embodiment short-circuits the lower bridge arm circuits of N power conversion units and connects sampling resistors in series to ground. This shared sampling resistor collects the single-phase current corresponding to N permanent magnet synchronous motors, reducing the number of sampling resistors and lowering costs. A single microcontroller simultaneously controls two motors, sampling both motor phase currents within a single PWM cycle and simultaneously controlling both inverters, achieving high real-time performance. Furthermore, by sharing a triangular wave generator, the microcontroller only requires a single timer interrupt to simultaneously control both motors, reducing requirements on the microcontroller. Furthermore, a low-cost dual-resistor sampling solution and shared sampling resistors further reduce costs.

[0147] While specific embodiments of the present disclosure have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of protection of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, and such changes and modifications are intended to fall within the scope of protection of the present disclosure.

Claims

1. A dual-resistance motor control circuit, characterized in that: The dual-resistance motor control circuit includes a main controller, a first-phase current sampling circuit, a second-phase current sampling circuit, and a third-phase current sampling circuit; The first phase current sampling circuit, the second phase current sampling circuit, and the third phase current sampling circuit each include N power conversion units, a first end of each power conversion unit is electrically connected to the main controller, and a second end of each power conversion unit is electrically connected to the same phase winding of different motors; Each of the power conversion units includes a drive circuit, an upper bridge arm circuit and a lower bridge arm circuit electrically connected to the drive circuit, the connection point between the upper bridge arm circuit and the lower bridge arm circuit is the second end, and one second end corresponds to one phase winding of the motor; The lower bridge arm circuit of each power conversion unit in the first phase current sampling circuit and the main controller are electrically connected to the third end of the first sampling resistor, and the fourth end of the first sampling resistor is grounded; The lower bridge arm circuit of each power conversion unit in the second phase current sampling circuit and the main controller are electrically connected to the fifth end of the second sampling resistor, and the sixth end of the second sampling resistor is grounded; The first phase current sampling circuit is used to collect the first phase currents of the N motors based on a sampling instruction, and transmit the first phase currents to the main controller; The second-phase current sampling circuit is used to collect the second-phase currents of the N motors based on the sampling instruction, and transmit the second-phase currents to the main controller; The main controller is used to obtain a corresponding third-phase current based on the first-phase current and the second-phase current of each motor, and control the operating state of each motor based on the first-phase current, the second-phase current and the third-phase current; Wherein, N is a positive integer greater than 1.

2. The dual-resistance motor control circuit according to claim 1, characterized in that: The first phase current sampling circuit further includes a first current amplifying unit, and the second phase current sampling circuit further includes a second current amplifying unit; The third end of the first sampling resistor is electrically connected to the main controller via the first current amplifying unit; The first current amplifying unit is used to amplify the input first phase current and transmit the amplified first phase current to the main controller; The fifth end of the second sampling resistor is electrically connected to the main controller via the second current amplifying unit; The second current amplifying unit is used to amplify the input second phase current and transmit the amplified second phase current to the main controller.

3. The dual-resistance motor control circuit according to claim 1, characterized in that: When N=2; The two power conversion units in the first phase current sampling circuit are respectively a first power conversion unit and a second power conversion unit; The two power conversion units in the second phase current sampling circuit are respectively a third power conversion unit and a fourth power conversion unit; The main controller is used to control the closed state of the first power conversion unit and the second power conversion unit to collect the first phase current of the first motor or the second motor; The main controller is further configured to control the closed state of the third power conversion unit and the fourth power conversion unit to collect the second phase current of the first motor or the second motor.

4. The dual-resistance motor control circuit according to claim 3, characterized in that: The main controller includes a signal generator; The signal generator is used to generate a PWM wave to control each of the motors based on the instructions of the main controller, and transmit the PWM wave to the corresponding motor via the first phase current sampling circuit, the second phase current sampling circuit and the third phase current sampling circuit to control the operating state of each of the motors.

5. The dual-resistance motor control circuit according to claim 4, characterized in that: The main controller further includes a timer, and the signal generator includes a triangle wave generator; The triangular wave generator is used to generate the PWM wave for controlling each of the motors; The timer is used to measure the period of the PWM wave; The main controller is used to determine the sampling moments of the first motor and the second motor based on the period of the PWM wave, and generate the sampling instruction at the sampling moments.

6. The dual-resistance motor control circuit according to claim 5, characterized in that: The main controller is used to control the triangle wave generator to generate a first PWM wave for controlling the first motor and a second PWM wave for controlling the second motor; The first power conversion unit includes a first upper bridge arm circuit and a first lower bridge arm circuit; The second power conversion unit includes a second upper bridge arm circuit and a second lower bridge arm circuit; The third power conversion unit includes a third upper bridge arm circuit and a third lower bridge arm circuit; The fourth power conversion unit includes a fourth upper bridge arm circuit and a fourth lower bridge arm circuit; The main controller is further configured to, at a first sampling moment, insert a first preset voltage vector into the first PWM wave, insert a second preset voltage vector into the second PWM wave, and control the first upper bridge arm circuit, the second lower bridge arm circuit, the third upper bridge arm circuit, and the fourth lower bridge arm circuit to be disconnected, and the first lower bridge arm circuit, the second upper bridge arm circuit, the third lower bridge arm circuit, and the fourth upper bridge arm circuit to be closed, so as to collect the first phase current and the second phase current of the first motor; The first sampling moment is an overflow moment or an underflow moment of the first PWM wave.

7. The dual-resistance motor control circuit according to claim 6, characterized in that: The main controller is further configured to, at a second sampling moment, insert a third preset voltage vector into the first PWM wave, insert a fourth preset voltage vector into the second PWM wave, and control the first lower bridge arm circuit, the second upper bridge arm circuit, the third lower bridge arm circuit, and the fourth upper bridge arm circuit to be disconnected, and the first upper bridge arm circuit, the second lower bridge arm circuit, the third upper bridge arm circuit, and the fourth lower bridge arm circuit to be closed, so as to collect the first phase current and the second phase current of the second motor; When the first sampling moment is the overflow moment, the second sampling moment is the underflow moment of the second PWM wave; when the first sampling moment is the underflow moment, the second sampling moment is the overflow moment of the second PWM wave.

8. The dual-resistance motor control circuit according to claim 7, characterized in that: The duration of the preset voltage vector is equal to the duration of the sampling window; and / or, The main controller is configured to obtain the corresponding third-phase current based on the following formula: in, is the third phase current, is the first phase current, is the second phase current.

9. The dual-resistance motor control circuit according to claim 8, characterized in that: The PWM wave generated by the triangular wave generator to control each of the motors satisfies the following conditions: Among them, D max is the maximum duty cycle corresponding to the PWM wave signal, T pwm is the signal period of the PWM wave, and T is the duration of the sampling window.

10. A motor control system, characterized in that: The motor control system includes N motors and the dual-resistor motor control circuit according to any one of claims 1 to 9.

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