DC permanent magnet brushless motor control circuit

Abstract

The invention provides a direct current permanent magnet brushless motor control circuit. Belongs to the field of motor control circuits. The zero-cross detection and motion detection circuit is used for performing zero-cross detection and motion detection; the phase comparison circuit is used for controlling the torque increase of the motor according to the output state; the auxiliary positioning control circuit starts the logic circuit and is used for enabling the rotor to leave a dead point rotor of the winding A; a rotor positioning control circuit for forward positioning current is formed in the winding A; the H switch power supply control circuit is used for providing a power supply with current limiting capability for the H switch circuit; the commutation logic circuit is used for generating control signals for driving the winding A and the winding B; and the H switching circuit is used for converting the control signal into a driving signal so as to finish torque adding of the motor rotor. Through the arrangement, the motor efficiency and the motor control precision can be improved.

Description

Technical Field

[0001] The present application relates to the field of motor circuits, and in particular, to a direct current permanent magnet brushless motor control circuit. Background Art

[0002] The motor control circuit is an electronic circuit that is mainly used to control the operation of the motor. This circuit can achieve precise control of the motor by controlling the motor power supply voltage, current and phase sequence.

[0003] Traditional motor control circuits are large in size, low in efficiency, and inaccurate in speed control. With the upgrading of the industry, in the instrumentation industry, more and more application scenarios require DC motors that are not only small in size, but also high in efficiency and high in control accuracy. Summary of the invention

[0004] The purpose of the present application is to provide a DC permanent magnet brushless motor control circuit, which can increase motor efficiency and improve motor control accuracy.

[0005] This application is implemented as follows:

[0006] The present application provides a DC permanent magnet brushless motor control circuit, comprising:

[0007] A reference frequency circuit, used for setting a reference frequency Uxt;

[0008] The zero-crossing detection and motion detection circuit is connected to the A winding and the B winding of the motor to perform zero-crossing detection and motion detection, and obtain zero-crossing detection output signals Aze and Bze of the A winding and the B winding. When the motor rotor passes a zero-crossing point, the circuit will output a motion detection pulse signal Urd;

[0009] The phase comparison circuit is used to compare the reference frequency Uxt with the motion detection pulse signal Urd, obtain the phase comparison output signal Phcom of the A winding and the B winding, and control the torque of the motor according to the output state;

[0010] The startup logic circuit includes an auxiliary positioning control circuit for outputting a control signal 1Delay to control the related circuit to form a reverse auxiliary positioning current in the B winding within a first preset time from the start-up moment, so as to allow the rotor to leave the dead point of the A winding; a rotor positioning control circuit for outputting a control signal 10Delay to control the related circuit to form a forward positioning current in the A winding within a second preset time from the start-up moment; and an H switch power supply control circuit for providing a power supply with a limited current capacity to the H switch circuit within a third preset time from the start-up moment; the first preset time, the second preset time, and the third preset time increase in sequence, and the related circuit includes a commutation logic circuit;

[0011] The commutation logic circuit is used to generate a control signal A for driving the A winding and the B winding according to the zero-crossing detection signals Aze and Bze of the A winding and the B winding and the phase comparison output signal Phcom through logical operation. d+ , A d- , B d+ , B d- ;

[0012] H switch circuit, used to drive the control signal A of winding A and winding B d+ , A d- , B d+ , B d- It is converted into driving signals for winding A and winding B to complete the torque application to the motor rotor.

[0013] Furthermore, the reference frequency circuit includes a binary counter D1 and a binary counter D2 connected to each other. The binary counter D1 and the crystal resonator form a vibration circuit and output a square wave signal after frequency division. The frequency f of the frequency reference signal Uxt is PEO for:

[0014]

[0015] Wherein, N is the product of the frequency division multiples of D1 and D2. Changing N can change the output frequency.

[0016] Further, the zero-crossing detection and motion detection circuit includes a zero-crossing detection circuit and a motion detection circuit;

[0017] The zero-crossing detection circuit uses two identical circuit structures to access the A winding and the B winding of the motor, wherein one circuit structure includes using an LM139A voltage comparator to complete the zero-crossing detection function, obtaining zero-crossing detection output signals Aze and Bze of the A winding and the B winding, resistors R2, R3, R4, and R5 connected to the LM139A voltage comparator divide the voltage of the motor winding, capacitor C1 removes sharp pulses in the winding voltage, diodes V1 and V2 are used to protect the LM139A voltage comparator, resistor R7 and capacitor C2 provide voltage feedback to the LM139A voltage comparator, and resistor R8 is used to provide a weak bias to the positive input terminal of the LM139A voltage comparator, so that it outputs a fixed high level in static state;

[0018] The motion detection circuit includes a logic gate D6C, a resistor R9, a capacitor C3, a logic gate D6D, a resistor R18, and a capacitor C7 to form a waveform edge detection circuit, which is used to output a pulse signal with a fixed width at its output end when the zero-crossing detection circuit changes state, and the logic gate D6B performs an XOR operation on the output of the waveform edge detection circuit to realize the motion detection function;

[0019] The zero-crossing detection output signals Aze and Bze of the A winding and the B winding are also output to the commutation logic circuit to provide a basis for commutation judgment. The resistor R10, the capacitor C4, the resistor R19, the capacitor C8 appropriately delay the output of the LM139A voltage comparator so that the zero-crossing detection output signal lags behind the motion detection output signal.

[0020] Furthermore, the phase comparison circuit includes a MC14046 phase-locked loop, wherein the AIN pin of the MC14046 phase-locked loop is the input end of the reference signal taken from the reference frequency Uxt, the BIN pin is the input end of the comparison signal, the comparison signal is taken from the motion detection pulse signal Urd, and UPC2 is the output end of the phase comparator; when the output state appears 1, it indicates that the phase of the comparison signal lags behind the reference signal; when the output state appears 0, it indicates that the phase of the comparison signal leads the reference signal; the output state 1 is used to control the torque applied to the motor so that the motor completes the starting process and runs in a synchronous state; the MC14046 phase-locked loop is connected to the logic gate D3A, and a resistor R1 is connected between the MC14046 phase-locked loop and the logic gate D3A, and the resistor R1 is used to convert the 3-state output of the phase comparator II into a state 0 output, and the logic gate D3A inverts the output of the phase comparator and completes the output buffer to obtain the phase comparison output signal Phcom.

[0021] Further;

[0022] The rotor auxiliary positioning control circuit includes a logic gate D6A, a resistor R44 and a capacitor C20. The logic gate D6A is used to output a control signal 1Delay to control the relevant circuit to form a reverse auxiliary positioning current in the B winding within the first preset time from the start-up moment, so that the rotor leaves the dead point of the A winding; the delay time can be adjusted by the resistor R44 and the capacitor C20;

[0023] The rotor positioning control circuit includes a logic gate D7A, a logic gate D7F, a resistor R46 and a capacitor C12. The logic gate D7A and the logic gate D7F are used to output a control signal 10Delay to control the relevant circuit to form a positive positioning current in the A winding within a second preset time from the start-up moment, so that the rotor can be reliably positioned. The delay time can be adjusted by the resistor R46 and the capacitor C12;

[0024] H switch power supply control circuit, including logic gate D7E, logic gate D7D, transistor V25, transistor V26, resistor R43 and capacitor C13;

[0025] Logic gate D7E, logic gate D7D, transistor V25 and transistor V26 are used to provide a power supply with a strong current limiting capability to the H switch circuit within the third preset time from the start-up moment, that is, the rotor positioning and initial start-up, to limit the current in the startup stage; thereafter, the power supply to the H switch is switched to the power supply for normal operation, and the delay time can be adjusted by resistor R43 and capacitor C13.

[0026] Furthermore, the first preset time is 1 s, the second preset time is 8.2 s, and the third preset time is 16.4 s.

[0027] Further, the commutation logic circuit includes connected logic gate D7C, logic gate D7B, logic gate D8C, logic gate D3B, logic gate D3C, logic gate D8D, logic gate D3D, logic gate D8B, logic gate D4A, logic gate D8A, logic gate D4B, logic gate D4C, logic gate D5B and logic gate D5A;

[0028] One input end of the logic gate D3B is connected to the phase comparison output signal Phcom, one input end of the logic gate D8B and the logic gate D3D is connected to the zero-crossing detection output signal Aze of the A winding, the other input end of the logic gate D8B, one input end of the logic gate D8C and the input end of the logic gate D7C are connected to the zero-crossing detection output signal Bze of the B winding; the output end of the logic gate D8A outputs the control signal A d+ , the output terminal of logic gate D4B outputs control signal A d- , the output terminal of logic gate D4C outputs control signal B d+ , the output of logic gate D5A outputs control signal B d- , where the control signal A d+ , control signal A d- They are the forward and reverse drive outputs of the A winding H switch; the control signal B d+ , control signal B d- They are the forward and reverse drive outputs of the B winding H switch.

[0029] Further, the H switch circuit includes two H switch circuit structures with the same structure to drive the A winding and the B winding respectively;

[0030] One of the H switch circuit structures includes an H switch power supply, a transistor V13, a transistor V14, a transistor V15, a transistor V16, a transistor V17 and a transistor V18; the base of the transistor V13 is connected to a control signal A via a resistor R20. d- The base of transistor V18 is connected to control signal A through resistor R24. d+ ; When the control signal A d+When the voltage reaches 0, transistor V18, transistor V14 and transistor V17 are turned on, and the current flows through the H switch power supply, transistor V14, the lead end of motor winding A1, the lead end of motor winding A2, transistor V17 and ground in sequence, and the motor A winding obtains the positive drive current; when A d- When a driving pulse arrives, transistors V13, V16 and V15 are turned on, and the current flows through the H switch power supply, transistor V16, the lead end of motor winding A2, the lead end of motor winding A1, transistor V15 and the ground in sequence. The motor winding A obtains a reverse driving current, and the effective value of the motor winding driving current is proportional to the driving pulse width;

[0031] Another H switch circuit structure includes an H switch power supply, a transistor V19, a transistor V20, a transistor V21, a transistor V22, a transistor V23 and a transistor V24; the base of the transistor V19 is connected to the control signal B through a resistor R25. d- The base of transistor V24 is connected to control signal B via resistor R29. d+ ; When the control signal B d+ When the voltage reaches the zero, transistors V24, V20 and V23 are turned on, and the current flows through the H switch power supply, transistor V20, the lead end of motor winding B1, the lead end of motor winding B2, transistor V23 and ground in sequence, and the motor B winding obtains the positive drive current; when B d- When a driving pulse arrives, transistor V18, transistor V22, and transistor V21 are turned on, and the current flows through the H switch power supply, transistor V22, the lead end of the motor winding B2, the lead end of the motor winding B1, transistor V21, and the ground in sequence. The motor winding B obtains a reverse driving current, and the effective value of the motor winding driving current is proportional to the driving pulse width.

[0032] Furthermore, the reference frequency Uxt is equal to the product of the rotation frequency of the motor and the number of pole pairs thereof.

[0033] Compared with the prior art, the present invention has at least the following advantages or beneficial effects:

[0034] The present invention provides a DC permanent magnet brushless motor circuit, which sets a reference frequency Uxt through a reference frequency circuit, realizes zero-crossing detection and motion detection through a zero-crossing detection and motion detection circuit, and outputs the zero-crossing detection output signals Aze and Bze of windings A and B to a commutation logic circuit, providing a basis for commutation discrimination, and performs appropriate delay to avoid the commutation logic circuit from generating unnecessary commutation burr signals. The phase comparison circuit compares the lead and lag of the reference frequency Uxt and the motion detection pulse signal Urd, obtains the phase comparison output signal of the A winding and the B winding, and controls the torque of the motor according to the output state, so that the motor completes the starting process and runs in a synchronous state. The starting logic circuit allows the rotor to leave the dead point of the A winding, controls the relevant circuit to form a positive positioning current in the A winding, and prevents the current in the starting stage from being too large. The commutation logic circuit generates a control signal A to drive the A and B windings. d+ , A d- , B d+ , B d- , so that the motor can complete acceleration and achieve synchronous operation. The H switch circuit is used to convert the control signal driving the A and B windings into the A and B winding drive signals to complete the torque addition to the motor rotor. This setting can increase the motor efficiency and improve the motor control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 This is a structural schematic diagram of a DC permanent magnet brushless motor control circuit for this application;

[0037] Figure 2 This is a circuit schematic diagram of a reference frequency circuit in a DC permanent magnet brushless motor control circuit of the present application;

[0038] Figure 3 This is a circuit schematic diagram of a zero-crossing detection and motion detection circuit in a DC permanent magnet brushless motor control circuit of the present application;

[0039] Figure 4 A circuit schematic diagram of a phase comparison circuit in a DC permanent magnet brushless motor control circuit of the present application;

[0040] Figure 5 The present application discloses a state diagram of a phase comparator in a DC permanent magnet brushless motor control circuit;

[0041] Figure 6 The present application provides a circuit schematic diagram of a start-up logic circuit in a DC permanent magnet brushless motor control circuit;

[0042] Figure 7 The present application provides a circuit schematic diagram of a commutation logic circuit in a DC permanent magnet brushless motor control circuit;

[0043] Figure 8 The present application discloses a circuit schematic diagram of an H switch circuit in a DC permanent magnet brushless motor control circuit;

[0044] Fig. 9A The present application discloses a circuit schematic diagram of a portion of a DC permanent magnet brushless motor control circuit;

[0045] Fig. 9B The present application provides a circuit schematic diagram of another part of a DC permanent magnet brushless motor control circuit.

[0046] icon:

[0047] 1. Reference frequency circuit; 2. Zero-crossing detection and motion detection circuit; 3. Phase comparison circuit; 4. Start-up logic circuit; 41. Auxiliary positioning control circuit; 42. Rotor positioning control circuit; 43. H switch power supply control circuit; 5. Commutation logic circuit; 6. H switch circuit. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0049] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0050] Example

[0051] The embodiment of the present application provides a DC permanent magnet brushless motor control circuit, which can increase motor efficiency and improve motor control accuracy.

[0052] Please refer to Figure 1 , Figure 1 The structure diagram of the DC permanent magnet brushless motor control circuit of the present invention is shown in FIG. The DC permanent magnet brushless motor control circuit comprises:

[0053] The reference frequency circuit 1 is used to set the reference frequency Uxt; specifically, the reference frequency is a standard frequency value used for comparison or reference. The reference frequency Uxt is equal to the product of the rotation frequency of the motor and its pole pair number; the rotation frequency of the motor refers to the number of revolutions per second (usually in Hertz Hz), and the pole pair number refers to the number of magnetic poles inside the motor. When the rotation frequency of the motor is multiplied by its pole pair number, the result is the reference frequency Uxt. If the rotation frequency of the motor increases or the pole pair number increases, the reference frequency Uxt will also increase accordingly.

[0054] The zero-crossing detection and motion detection circuit 2 is connected to the A winding and the B winding of the motor, and is used for zero-crossing detection and motion detection, and obtains the zero-crossing detection output signals Aze and Bze of the A winding and the B winding. When the motor rotor passes a zero-crossing point, the circuit will output a motion detection pulse signal Urd; specifically, the circuit can not only perform zero-crossing detection, but also perform motion detection. Zero-crossing detection refers to detecting when the current or voltage waveform crosses the zero point (i.e., from positive to negative or from negative to positive), while motion detection refers to detecting whether the motor is moving. The circuit is connected to the A winding and the B winding of the motor, and the A winding and the B winding are used to generate a rotating magnetic field to drive the motor rotor to rotate. When the circuit performs zero-crossing detection, it generates two output signals: Aze and Bze. These two signals correspond to the zero-crossing detection results of the A winding and the B winding, respectively. These signals can be logic levels (such as high level or low level) to indicate when the corresponding winding current or voltage waveform crosses the zero point. In addition to the zero-crossing detection output signal, the circuit can also output a motion detection pulse signal Urd every time the motor rotor passes a zero-crossing point. This signal can be a short pulse to indicate that the motor rotor is moving and has passed a specific electrical position (i.e., zero-crossing point).

[0055] The phase comparison circuit 3 is used to compare the reference frequency Uxt with the motion detection pulse signal Urd, obtain the phase comparison output signal Phcom of the A winding and the B winding, and control the torque of the motor according to the output state; specifically, the phase is a parameter that describes the position of the waveform (such as a sine wave) on the time axis, and the phase comparison circuit 3 can detect and compare the phase difference between the two waveforms. By comparing the phase lead or lag of the reference frequency Uxt and the motion detection pulse signal Urd, the phase comparison circuit 3 generates an output signal Phcom. This signal can be a logic level (such as a high level or a low level) to indicate the lead or lag relationship between the two input signals. The output signal Phcom of the phase comparison circuit 3 is used to control the torque of the motor. According to the state of the Phcom signal (such as a high level or a low level), the motor control system can adjust the torque output of the motor. For example, if the Phcom signal indicates that the motor rotor lags behind the reference point (that is, the phase represented by the reference frequency Uxt), the control system may increase the torque of the motor to accelerate the rotor. On the contrary, if the rotor is ahead of the reference point, the torque can be reduced to decelerate.

[0056] The startup logic circuit 4 includes an auxiliary positioning control circuit 41 for outputting a control signal 1Delay to control the relevant circuit to form a reverse auxiliary positioning current in the B winding within the first preset time from the startup moment, so that the rotor leaves the dead point of the A winding; a rotor positioning control circuit 42 for outputting a control signal 10Delay to control the relevant circuit to form a forward positioning current in the A winding within the second preset time from the startup moment; an H switch power supply control circuit 43 for providing a power supply with a limited current capacity to the H switch circuit 6 within the third preset time from the startup moment; the first preset time, the second preset time, and the third preset time increase in sequence, and the relevant circuit includes a commutation logic circuit 5; specifically, within the first preset time from the startup moment, preferably within 1s within the first preset time, the startup logic circuit 4 will output a control signal 1Delay. This signal controls the relevant circuit (including the commutation logic circuit 5, etc.) to form a reverse auxiliary positioning current in the B winding. The function of this reverse current is to help the rotor leave the dead point position of the A winding. The dead point refers to the state in which the rotor cannot continue to rotate due to the balance of electromagnetic force when the motor is at a specific position. By introducing a reverse auxiliary positioning current, this balance can be broken, allowing the rotor to start smoothly. Next, within the second preset time from the start-up moment, the second preset time is preferably 8.2s, and the start logic circuit 4 will output another control signal 10Delay. This signal controls the relevant circuit to form a forward positioning current in the A winding. The role of this forward current is to further position the rotor to ensure that it starts to rotate in the correct position. This helps to reduce vibration and noise during startup and improve the starting efficiency of the motor. Within the third preset time, the third preset time is preferably 16.4s, the start logic circuit 4 will provide the H switch circuit 6 with a power supply with limited current capacity. The function of this power supply is to control the current size when the motor starts to prevent excessive current from damaging the motor or related circuits. The power supply can adjust the output current size as needed to ensure that the motor starts within a safe range.

[0057] The commutation logic circuit 5 is used to generate a control signal A for driving the A winding and the B winding according to the zero-crossing detection signals Aze and Bze of the A winding and the B winding and the phase comparison output signal Phcom through logic operation. d+ , A d- , B d+ , B d-Specifically, the input signals of the commutation logic circuit 5 include zero-crossing detection signals Aze and Bze of the A winding and the B winding, and the phase comparison output signal Phcom. These signals provide important information about the current operating state of the motor. Aze and Bze are zero-crossing detection signals, which are generated when the current or voltage waveforms of the A winding and the B winding cross the zero point respectively. These signals are used to determine the electrical position of the motor. Phcom is a phase comparison output signal, which reflects the phase relationship between the reference frequency Uxt and the motion detection pulse signal Urd. This signal is used to determine the position or motion state of the motor rotor relative to a certain reference point. The commutation logic circuit 5 performs logical operations on the input signals, which may include basic logical operations such as AND, OR, and NOT, as well as more complex combinational logic or sequential logic. The purpose of the logical operation is to generate appropriate control signals according to the state of the input signal. Through logical operations, the commutation logic circuit 5 generates control signals for driving the A winding and the B winding. These control signals include direction control signals (used to determine the direction of the current) and enable signals (used to control the on and off of the current). These signals are sent to the motor's power circuit (such as an inverter or converter) to control the current in the A and B windings, thereby controlling the direction and speed of the motor's rotation.

[0058] H switch circuit 6, used to drive the control signal A of winding A and winding B d+ , A d- , B d+ , B d- Converted into drive signals for winding A and winding B to complete the torque addition to the motor rotor. Specifically, its circuit structure is similar to the shape of the letter "H", consisting of four switches (usually transistors or relays), which can be opened or closed independently to control the direction and size of the current. The main function of the H switch circuit 6 is to convert the control signals for driving winding A and winding B into actual drive signals for winding A and winding B. This means that it receives output signals (i.e., control signals) from a motor controller or other control logic, and opens or closes its internal switches according to the states of these signals, thereby controlling the path and size of the current passing through winding A and winding B. Control signals are instructions for instructing the motor on how to operate, and they may include information such as the direction, size, and when to start and stop of the current. However, these control signals are usually low-level signals, which are not enough to directly drive the motor windings to generate the required current. Therefore, the role of the H switch circuit 6 is to convert these low-level control signals into high-level, high-current drive signals that can drive the motor windings. The driving signal converted by the H switch circuit 6 will generate the required current in the A winding and the B winding, and the magnetic field generated by these currents will interact with the permanent magnet or electromagnet of the motor rotor, thereby generating torque (i.e., torque addition) to drive the motor rotor to rotate.

[0059] Please refer to Figure 2 , Fig. 9A and Fig. 9B , Figure 2 This is a circuit schematic diagram of the reference frequency circuit 1 in the DC permanent magnet brushless motor control circuit of this application, Fig. 9A It is a part of the overall circuit diagram of the DC permanent magnet brushless motor control circuit of this application; Fig. 9B This is another part of the overall circuit diagram of the DC permanent magnet brushless motor control circuit of this application. Further, the reference frequency circuit 1 includes a binary counter D1 and a binary counter D2 connected to each other. The binary counter D1 and the crystal resonator form a vibration circuit and output a square wave signal after frequency division. The frequency f of the frequency reference signal Uxt is PEO for:

[0060]

[0061] Wherein, N is the product of the frequency division multiples of D1 and D2. Changing N can change the output frequency.

[0062] Please refer to Figure 3 , Figure 3 The circuit schematic diagram of the zero-crossing detection and motion detection circuit 2 in the DC permanent magnet brushless motor control circuit of the present application, further, the zero-crossing detection and motion detection circuit 2 includes a zero-crossing detection circuit and a motion detection circuit;

[0063] The zero-crossing detection circuit adopts two identical circuit structures to access the A winding and the B winding of the motor, wherein one circuit structure includes using the LM139A voltage comparator to complete the zero-crossing detection function, obtaining the zero-crossing detection output signals Aze and Bze of the A winding and the B winding, the resistors R2, R3, R4 and R5 connected to the LM139A voltage comparator divide the voltage of the motor winding, the capacitor C1 removes the sharp pulse in the winding voltage, the diodes V1 and V2 are used to protect the LM139A voltage comparator, the resistor R7 and the capacitor C2 provide voltage feedback to the LM139A voltage comparator, and the resistor R8 is used to provide a weak bias to the positive input terminal of the LM139A voltage comparator, so that it outputs a fixed high level in static state; through the setting provided, the LM139A voltage comparator works in a safe state with strong anti-interference ability and rapid output flipping, and outputs a reliable signal to the subsequent circuit.

[0064] The motion detection circuit includes a logic gate D6C, a resistor R9, a capacitor C3, a logic gate D6D, a resistor R18, and a capacitor C7 to form a waveform edge detection circuit. When the zero-crossing detection circuit changes state, its output end outputs a pulse signal with a fixed width. The logic gate D6B performs an XOR operation on the output of the waveform edge detection circuit to realize the motion detection function; that is, every time the motor rotor passes a zero-crossing point, the circuit will output a detection pulse Urd.

[0065] The zero-crossing detection output signals Aze and Bze of the A winding and the B winding are also output to the commutation logic circuit 5 to provide a basis for commutation judgment. The resistor R10, the capacitor C4, the resistor R19, and the capacitor C8 appropriately delay the output of the LM139A voltage comparator so that the zero-crossing detection output signal lags behind the motion detection output signal, thereby avoiding the commutation logic circuit 5 from generating unnecessary commutation glitch signals.

[0066] Please refer to Figure 4 and Figure 5 , Figure 4 This is a circuit schematic diagram of the phase comparison circuit 3 in the DC permanent magnet brushless motor control circuit of this application, Figure 5The phase comparator state diagram of the present application, further, the phase comparison circuit 3 includes a MC14046 phase-locked loop, the AIN pin of the MC14046 phase-locked loop is the input end of the reference signal taken from the reference frequency Uxt, the BIN pin is the input end of the comparison signal, the comparison signal is taken from the motion detection pulse signal Urd, and UPC2 is the output end of the phase comparator; when the output state appears 1, it indicates that the phase of the comparison signal lags behind the reference signal; when the output state appears 0, it indicates that the phase of the comparison signal is ahead of the reference signal; the output state 1 is used to control the torque applied to the motor, so that the motor completes the starting process and runs in a synchronous state; the MC14046 phase-locked loop is connected to the logic gate D3A, and a resistor R1 is connected between the MC14046 phase-locked loop and the logic gate D3A. The resistor R1 is used to convert the 3-state output of the phase comparator II into a state 0 output, and the logic gate D3A inverts the output of the phase comparator and completes the output buffer to obtain the phase comparison output signal Phcom. Specifically, when the comparison signal phase lags behind the reference signal, the input state "10" always comes out earlier than "11", and the "00" state may be included in the middle. Analysis of the phase comparator state diagram shows that: when the reference signal jumps from "0" to "1", the output state becomes "1", and the output state does not change to "3-state" until the comparison signal has "1". In other words, when the output state appears "1", it means that the comparison signal phase lags behind the reference signal, and the width of "1" corresponds to the phase lag. When the comparison signal phase leads the reference signal (that is, when a motion detection signal appears), the input state "01" always appears earlier than "11". Analysis of the state diagram shows that: when the comparison signal jumps from "0" to "1", the output state becomes "0", and the output state does not change to "3-state" until the reference signal has "1". In other words, when the output state appears "0", it means that the comparison signal phase leads the reference signal, and the width of "0" corresponds to the phase advance. Therefore, the output state "1" can be used to control the torque applied to the motor, so that the motor completes the startup process and runs in a synchronous state. In fact, since there is always resistance and friction in the operation of the motor, after the motor reaches the synchronous speed, the phase of the comparison signal still lags slightly behind the reference signal. The degree of lag reflects the size of the resistance and friction, and also determines the amount of power drawn from the power supply.

[0067] The function of resistor R1 is to convert the "3-state" output of phase comparator II to a "0" output. D3A inverts the output of the phase comparator and completes the output buffer.

[0068] Please refer to Figure 6 , Figure 6 This is a circuit schematic diagram of the start-up logic circuit 4 in the DC permanent magnet brushless motor control circuit of the present application. Further, the start-up logic circuit 4 includes a rotor auxiliary positioning control circuit 41, a rotor positioning control circuit 42 and an H switch power supply control circuit 43;

[0069] The rotor auxiliary positioning control circuit 41 includes a logic gate D6A, a resistor R44 and a capacitor C20. The logic gate D6A is used to output a control signal 1Delay to control the relevant circuit to form a reverse auxiliary positioning current in the B winding within a first preset time, such as 1 second, from the start-up moment, so as to make the rotor leave the dead point of the A winding. The circuit is actually a delay circuit, and its delay time can be adjusted by the resistor R44 and the capacitor C20.

[0070] The rotor positioning control circuit 42 includes a logic gate D7A, a logic gate D7F, a resistor R46 and a capacitor C12. The logic gate D7A and the logic gate D7F are used to output a control signal 10Delay to control the relevant circuit to form a positive positioning current in the A winding within a second preset time from the start-up time, for example, within 8.2 seconds, so that the rotor can be reliably positioned. The circuit is also a delay circuit. The delay time can be adjusted by the resistor R46 and the capacitor C12;

[0071] The H switch power supply control circuit 43 includes a logic gate D7E, a logic gate D7D, a transistor V25, a transistor V26, a resistor R43 and a capacitor C13; the logic gate D7E, the logic gate D7D, the transistor V25 and the transistor V26 are used to provide a power supply with a strong current limiting capability to the H switch circuit 6 within a third preset time from the start-up moment, for example, within 16.4 seconds, that is, within the initial stage of rotor positioning and starting, to limit the current in the starting stage from being too large; thereafter, the power supply to the H switch is switched to the power supply for normal operation, and the delay time can be adjusted by the resistor R43 and the capacitor C13.

[0072] Please refer to Figure 7 , Figure 7 The circuit schematic diagram of the commutation logic circuit 5 in the DC permanent magnet brushless motor control circuit of the present application. Further, the commutation logic circuit 5 includes connected logic gates D7C, logic gate D7B, logic gate D8C, logic gate D3B, logic gate D3C, logic gate D8D, logic gate D3D, logic gate D8B, logic gate D4A, logic gate D8A, logic gate D4B, logic gate D4C, logic gate D5B and logic gate D5A; A d+

[0073] One input end of the logic gate D3B is connected to the phase comparison output signal Phcom, one input end of the logic gate D8B and the logic gate D3D is connected to the zero-crossing detection output signal Aze of the A winding, the other input end of the logic gate D8B, one input end of the logic gate D8C and the input end of the logic gate D7C are connected to the zero-crossing detection output signal Bze of the B winding; the output end of the logic gate D8A outputs the control signal A d+ , the output terminal of logic gate D4B outputs control signal A d-, the output terminal of logic gate D4C outputs control signal B d+ , the output of logic gate D5A outputs control signal B d- , where the control signal A d+ , control signal A d- They are the forward and reverse drive outputs of the A winding H switch; the control signal B d+ , control signal B d- They are the forward and reverse drive outputs of the B winding H switch. For specific commutation logic, please refer to the following formula.

[0074]

[0075] When the 10Delay signal is "0", that is, during the rotor positioning period within 8.2 seconds after power-on, A d+ =1,A d- =0,B d+ =0, The circuit output meets the requirements of rotor positioning timing.

[0076] When the 10Delay signal is "1", formulas (2) and (3) yield:

[0077]

[0078] Formulas (6) to (9) show that at this time, each driver is When When it is "1", the output phase sequence of each drive is A d+ →B d- →A d- →B d+ →A d+ Cycle. When it is "0", there is no drive output. Under such a drive signal, the motor completes acceleration and achieves synchronous operation.

[0079] Please refer to Figure 8 , Figure 8 The circuit schematic diagram of the H switch circuit 6 in the DC permanent magnet brushless motor control circuit of the present application. Further, the H switch circuit 6 includes two H switch circuits 6 with the same structure, which respectively drive the A winding and the B winding;

[0080] One of the H switch circuits 6 includes an H switch power supply, a transistor V13, a transistor V14, a transistor V15, a transistor V16, a transistor V17 and a transistor V18; the base of the transistor V13 is connected to the control signal A via a resistor R20. d- The base of transistor V18 is connected to control signal A through resistor R24. d+ ; When the control signal A d+When the voltage reaches 0, transistor V18, transistor V14 and transistor V17 are turned on, and the current flows through the H switch power supply, transistor V14, the lead end of motor winding A1, the lead end of motor winding A2, transistor V17 and ground in sequence, and the motor A winding obtains the positive drive current; when A d- When a driving pulse arrives, transistors V13, V16 and V15 are turned on, and the current flows through the H switch power supply, transistor V16, the lead end of motor winding A2, the lead end of motor winding A1, transistor V15 and ground in sequence, and the motor winding A obtains a reverse driving current. The effective value of the motor winding driving current is proportional to the driving pulse width. Specifically, the control signal A d+ , A d- , B d+ , B d- The drive signal output by the commutation logic circuit 5, A1, A2 are connected to the lead-out terminal of the A winding, B1, B2 are connected to the lead-out terminal of the B winding, and the H switch power supply is provided for the start logic circuit 4. d+ When a driving pulse arrives, transistors V18, V14, and V17 are turned on, and the current flows from the H switch power supply → V14 → the lead end of the motor winding A1 → the lead end of the motor winding A2 → V17 → ground, and the motor A winding receives a positive driving current; when A d- When a driving pulse arrives, V13, V16, and V15 are turned on, and the current flows from the H switch power supply → V16 → the lead end of the motor winding A2 → the lead end of the motor winding A1 → V15 → ground, and the motor winding A receives a reverse driving current. The effective value of the motor winding driving current is proportional to the driving pulse width.

[0081] Another H switch circuit 6 structure includes an H switch power supply, a transistor V19, a transistor V20, a transistor V21, a transistor V22, a transistor V23 and a transistor V24; the base of the transistor V19 is connected to the control signal B through a resistor R25. d- The base of transistor V24 is connected to control signal B via resistor R29. d+ ; When the control signal B d+ When the voltage reaches the zero, transistors V24, V20 and V23 are turned on, and the current flows through the H switch power supply, transistor V20, the lead end of motor winding B1, the lead end of motor winding B2, transistor V23 and ground in sequence, and the motor B winding obtains the positive drive current; when B d- When a driving pulse arrives, transistor V18, transistor V22, and transistor V21 are turned on, and the current flows through the H switch power supply, transistor V22, the lead end of the motor winding B2, the lead end of the motor winding B1, transistor V21, and the ground in sequence. The motor winding B obtains a reverse driving current, and the effective value of the motor winding driving current is proportional to the driving pulse width.

[0082] It will be apparent to those skilled in the art that the present application is not limited to the details of the exemplary embodiments described above, and that the present application can be implemented in other specific forms without departing from the spirit or essential features of the present application. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present application. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A DC permanent magnet brushless motor control circuit, characterized in that: include: A reference frequency circuit, used for setting a reference frequency Uxt; The zero-crossing detection and motion detection circuit is connected to the A winding and the B winding of the motor to perform zero-crossing detection and motion detection, and obtain zero-crossing detection output signals Aze and Bze of the A winding and the B winding. When the motor rotor passes a zero-crossing point, the circuit will output a motion detection pulse signal Urd; The phase comparison circuit is used to compare the reference frequency Uxt with the motion detection pulse signal Urd, obtain the phase comparison output signal Phcom of the A winding and the B winding, and control the torque of the motor according to the output state; The startup logic circuit includes an auxiliary positioning control circuit for outputting a control signal 1Delay to control the related circuit to form a reverse auxiliary positioning current in the B winding within a first preset time from the start-up moment, so as to allow the rotor to leave the dead point of the A winding; a rotor positioning control circuit for outputting a control signal 10Delay to control the related circuit to form a forward positioning current in the A winding within a second preset time from the start-up moment; and an H switch power supply control circuit for providing a power supply with a limited current capacity to the H switch circuit within a third preset time from the start-up moment; the first preset time, the second preset time, and the third preset time increase in sequence, and the related circuit includes a commutation logic circuit; The commutation logic circuit is used to generate a control signal A for driving the A winding and the B winding according to the zero-crossing detection signals Aze and Bze of the A winding and the B winding and the phase comparison output signal Phcom through logical operation. d+ , A d- , B d+ , B d- ; H switch circuit, used to drive the control signal A of winding A and winding B d+ , A d- , B d+ , B d- It is converted into driving signals for winding A and winding B to complete the torque application to the motor rotor.

2. A DC permanent magnet brushless motor control circuit according to claim 1, characterized in that: The reference frequency circuit includes a binary counter D1 and a binary counter D2 connected to each other. The binary counter D1 and the crystal resonator form a vibration circuit and output a square wave signal after frequency division. The frequency f of the frequency reference signal Uxt is PEO for: Wherein, N is the product of the frequency division multiples of D1 and D2. Changing N can change the output frequency.

3. A DC permanent magnet brushless motor control circuit according to claim 1, characterized in that: The zero-crossing detection and motion detection circuit comprises a zero-crossing detection circuit and a motion detection circuit; The zero-crossing detection circuit uses two identical circuit structures to access the A winding and the B winding of the motor, wherein one circuit structure includes using an LM139A voltage comparator to complete the zero-crossing detection function, obtaining zero-crossing detection output signals Aze and Bze of the A winding and the B winding, resistors R2, R3, R4, and R5 connected to the LM139A voltage comparator divide the voltage of the motor winding, capacitor C1 removes sharp pulses in the winding voltage, diodes V1 and V2 are used to protect the LM139A voltage comparator, resistor R7 and capacitor C2 provide voltage feedback to the LM139A voltage comparator, and resistor R8 is used to provide a bias to the positive input terminal of the LM139A voltage comparator so that it outputs a fixed high level in static state; The motion detection circuit includes a logic gate D6C, a resistor R9, a capacitor C3, a logic gate D6D, a resistor R18, and a capacitor C7 to form a waveform edge detection circuit, which is used to output a pulse signal with a fixed width at its output end when the zero-crossing detection circuit changes state, and the logic gate D6B performs an XOR operation on the output of the waveform edge detection circuit to realize the motion detection function; The zero-crossing detection output signals Aze and Bze of the A winding and the B winding are also output to the commutation logic circuit to provide a basis for commutation judgment. The output of the LM139A voltage comparator is delayed by resistor R10, capacitor C4, resistor R19, and capacitor C8, so that the zero-crossing detection output signal lags behind the motion detection output signal.

4. A DC permanent magnet brushless motor control circuit according to claim 3, characterized in that: The phase comparison circuit includes a MC14046 phase-locked loop, wherein the AIN pin of the MC14046 phase-locked loop is the input end of the reference signal taken from the reference frequency Uxt, the BIN pin is the input end of the comparison signal, the comparison signal is taken from the motion detection pulse signal Urd, and UPC2 is the output end of the phase comparator; When the output state is 1, it means that the comparison signal phase lags behind the reference signal; When the output state appears to be 0, it indicates that the comparison signal phase is ahead of the reference signal; the output state 1 is used to control the torque applied to the motor so that the motor completes the starting process and runs in a synchronous state; the MC14046 phase-locked loop is connected to the logic gate D3A, and a resistor R1 is connected between the MC14046 phase-locked loop and the logic gate D3A. The resistor R1 is used to convert the 3-state output of the phase comparator II into a state 0 output. The logic gate D3A inverts the output of the phase comparator and completes the output buffering to obtain the phase comparison output signal Phcom.

5. A DC permanent magnet brushless motor control circuit according to claim 1, characterized in that ； The rotor auxiliary positioning control circuit includes a logic gate D6A, a resistor R44 and a capacitor C20. The logic gate D6A is used to output a control signal 1Delay to control the relevant circuit to form a reverse auxiliary positioning current in the B winding within the first preset time from the start-up moment, so as to make the rotor leave the dead point of the A winding; Its delay time can be adjusted by resistor R44 and capacitor C20; The rotor positioning control circuit includes a logic gate D7A, a logic gate D7F, a resistor R46 and a capacitor C12. The logic gate D7A and the logic gate D7F are used to output a control signal 10Delay to control the relevant circuit to form a positive positioning current in the A winding within a second preset time from the start-up moment, so that the rotor can be reliably positioned. The delay time can be adjusted by the resistor R46 and the capacitor C12; The H switch power supply control circuit includes a logic gate D7E, a logic gate D7D, a transistor V25, a transistor V26, a resistor R43 and a capacitor C13; the logic gate D7E, the logic gate D7D, the transistor V25 and the transistor V26 are used to provide a power supply with a strong current limiting capability to the H switch circuit within a third preset time from the start-up moment, that is, the rotor positioning and the initial start-up period, to limit the current in the start-up period; thereafter, the power supply to the H switch is switched to the power supply for normal operation, and the delay time can be adjusted by the resistor R43 and the capacitor C13.

6. A DC permanent magnet brushless motor control circuit according to claim 5, characterized in that: The first preset time is 1 s, the second preset time is 8.2 s, and the third preset time is 16.4 s.

7. A DC permanent magnet brushless motor control circuit according to claim 5, characterized in that: The commutation logic circuit includes connected logic gate D7C, logic gate D7B, logic gate D8C, logic gate D3B, logic gate D3C, logic gate D8D, logic gate D3D, logic gate D8B, logic gate D4A, logic gate D8A, logic gate D4B, logic gate D4C, logic gate D5B and logic gate D5A; One input end of the logic gate D3B is connected to the phase comparison output signal Phcom, one input end of the logic gate D8B and the logic gate D3D is connected to the zero-crossing detection output signal Aze of the A winding, the other input end of the logic gate D8B, one input end of the logic gate D8C and the input end of the logic gate D7C are connected to the zero-crossing detection output signal Bze of the B winding; the output end of the logic gate D8A outputs the control signal A d+ , the output terminal of logic gate D4B outputs control signal A d- , the output terminal of logic gate D4C outputs control signal B d+ , the output of logic gate D5A outputs control signal B d- , where the control signal A d+ , control signal A d- They are the forward and reverse drive outputs of the A winding H switch; the control signal B d+ , control signal B d- They are the forward and reverse drive outputs of the B winding H switch.

8. A DC permanent magnet brushless motor control circuit according to claim 7, characterized in that: The H switch circuit includes two H switch circuit structures with the same structure, driving the A winding and the B winding respectively; One of the H switch circuit structures includes an H switch power supply, a transistor V13, a transistor V14, a transistor V15, a transistor V16, a transistor V17 and a transistor V18; the base of the transistor V13 is connected to a control signal A via a resistor R20. d- The base of transistor V18 is connected to control signal A through resistor R24. d + ; When the control signal A d+ When the voltage reaches 0, transistor V18, transistor V14 and transistor V17 are turned on, and the current flows through the H switch power supply, transistor V14, the lead end of motor winding A1, the lead end of motor winding A2, transistor V17 and ground in sequence, and the motor A winding obtains the positive drive current; when A d- When a driving pulse arrives, transistors V13, V16 and V15 are turned on, and the current flows through the H switch power supply, transistor V16, the lead end of motor winding A2, the lead end of motor winding A1, transistor V15 and the ground in sequence. The motor winding A obtains a reverse driving current, and the effective value of the motor winding driving current is proportional to the driving pulse width; Another H switch circuit structure includes an H switch power supply, a transistor V19, a transistor V20, a transistor V21, a transistor V22, a transistor V23 and a transistor V24; the base of the transistor V19 is connected to the control signal B through a resistor R25. d- The base of transistor V24 is connected to control signal B via resistor R29. d+ ; When the control signal B d+ When the voltage reaches the zero, transistors V24, V20 and V23 are turned on, and the current flows through the H switch power supply, transistor V20, the lead end of motor winding B1, the lead end of motor winding B2, transistor V23 and ground in sequence, and the motor B winding obtains the positive drive current; when B d- When a driving pulse arrives, transistor V18, transistor V22, and transistor V21 are turned on, and the current flows through the H switch power supply, transistor V22, the lead end of the motor winding B2, the lead end of the motor winding B1, transistor V21, and the ground in sequence. The motor winding B obtains a reverse driving current, and the effective value of the motor winding driving current is proportional to the driving pulse width.

9. A DC permanent magnet brushless motor control circuit according to claim 1, characterized in that: The reference frequency Uxt is equal to the product of the rotation frequency of the motor and the number of pole pairs thereof.

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