WO2023226253A1

WO2023226253A1 - Permanent-magnet electric motor system and soft start method

Info

Publication number: WO2023226253A1
Application number: PCT/CN2022/119514
Authority: WO
Inventors: 韦荣星; 孙海荣
Original assignee: 中山大洋电机股份有限公司
Priority date: 2022-05-25
Filing date: 2022-09-19
Publication date: 2023-11-30
Also published as: CN114665758B; CN114665758A

Abstract

Disclosed in the present invention are a permanent-magnet electric motor system and a soft start method. The permanent-magnet electric motor system comprises a electric motor unit and an electric motor controller. The electric motor controller comprises a power supply circuit, an electric motor microcontroller unit (MCU) and an inverter circuit, and the electric motor controller further comprises a sampling and driving circuit and an electronic switch Q1, wherein a control end of the electronic switch Q1 is electrically connected to a signal output end of the sampling and driving circuit. The electric motor is powered on and started up, and when the electric motor MCU does not output a signal to the inverter circuit, the inverter circuit stops working; the sampling and driving circuit samples a synchronization signal of an externally inputted alternating current, analyzes and processes the synchronization signal of the externally inputted alternating current, and then controls the turning-on/turning-off of the electronic switch Q1, so as to realize stepped charging of an electrolytic capacitor C1; and after charging of the electrolytic capacitor C1 is completed, the sampling and driving circuit sends out a signal to notify the electric motor MCU that charging of the electrolytic capacitor C1 has been completed, such that the electric motor can be started up.

Description

A permanent magnet motor system and soft starting method

Technical field

The invention relates to a permanent magnet motor system and a soft starting method.

Background technique

DC motor input rectifier filter circuits all have the problem of mains switch impact. The reason is caused by the charging of the filter capacitor. The larger the capacitor, the greater the input impact current, which can easily interfere with the equipment and even cause fluctuations in the power grid. In more serious cases, the input fuse can be burned. It will cause the risk of permanent failure of the rectifier bridge, capacitor, etc. of the rectifier circuit. Therefore, to solve this problem, the thermistor NTC or the power resistor PTC parallel relay is selected to reduce the impact. When the mains is switched on and off, the impact current is reduced and the impact on the power grid is reduced. The impact is frequent, so various circuits specifically targeted at impact applications have emerged, referred to as buffer circuits or soft-start circuits; the current common soft-start circuits can be referred to Figure 1 and Figure 2.

The above two soft-start circuits have the following defects:

1) The soft start circuit as shown in Figure 1 starts when it is cold. The current passes through the fuse F1, resistor NTC1, capacitor CX, and inductor L1. After being filtered by the EMI filter circuit, it flows to the rectifier bridge B1 and reaches the capacitor C1. The resistor NTC1 is cold. The resistance value is relatively large, and the capacitor C1 of the subsequent rectifier circuit is slowly charged. At this time, the charging current is relatively small, and current passes through the resistor NTC1, causing power consumption and the temperature rises. As the temperature increases, the value of the resistor NTC1 gradually becomes smaller, and the current gradually becomes smaller. Large, the value of resistor NTC1 when in the hot state is relatively small, close to a short-circuit state. At this time, the power-off startup impulse current is large, and there is a risk of failure; the normal working resistor NTC1 continues to have current flowing through it, maintaining a high temperature state, causing large losses and causing damage to nearby components. It has an impact on electronic circuits and reduces the reliability of the circuit, especially the temperature-sensitive component capacitors. High temperatures will directly reduce their lifespan;

2) The soft start circuit shown in Figure 2. When starting, the current passes through the resistor R1 to charge the capacitor C1. After the charging is completed, the relay RY1 acts to close, short-circuiting the resistor R1, solving the problem of voltage drop and power consumption in the resistor, but the relay RY1 switches There is a delay. After a power outage and a power-on shock without reset, the current will flow directly to the downstream circuit through the relay RY1 contact to charge the capacitor C1. At this time, the circuit loses the soft-start function and cannot achieve the purpose of soft-start.

Contents of the invention

An object of the present invention is to provide a permanent magnet motor system and a soft start method that can solve the problem in the prior art that the thermistor has a small resistance value in a hot state, a large current impact, and the risk of failure, and the thermistor works normally. There is a technical problem of continuous current flowing through, high temperature state and high loss, which will also affect nearby electronic circuits and reduce the reliability of the circuit.

Another object of the present invention is to provide a permanent magnet motor system and a soft start method, which can solve the problem in the prior art that the connection of the resistor parallel relay is powered on and started when the power fails and is not reset, and the current flows directly from the relay contact, and the power The resistance loses its function and the current impact is large, which is a technical problem.

The object of the present invention is achieved through the following technical solutions.

An object of the present invention is to provide a permanent magnet motor system, which includes a motor unit and a motor controller. The motor unit includes a rotor assembly and a stator assembly. The motor controller includes a power supply circuit, a motor microprocessor MCU and an inverter circuit. , the power supply circuit supplies power to each part of the circuit, and the motor microprocessor MCU controls the operation of the motor unit through the inverter circuit;

The power supply circuit includes a filter circuit, a rectifier circuit, an electrolytic capacitor C1 and a discharge resistor R1. The externally input alternating current is processed by the filter circuit and the rectifier circuit to charge the electrolytic capacitor C1. The voltage output terminal A of the rectifier circuit is connected to one end of the electrolytic capacitor C1. , the discharge resistor R1 is connected in parallel to both ends of the electrolytic capacitor C1;

The motor controller also includes a sampling and driving circuit and an electronic switch Q1. One end of the discharge resistor R1 is electrically connected to the voltage output terminal A of the rectifier circuit, and the other end is connected to the ground through the electronic switch Q1. The control end of the electronic switch Q1 is connected to the sampling and driving circuit. The signal output terminal is electrically connected;

When the motor is powered on and started, the motor microprocessor MCU does not output a signal to the inverter circuit, and the inverter circuit stops working. The sampling and driving circuit is used to sample the externally input AC synchronization signal, and analyze and process the externally input AC synchronization signal. Afterwards, the electronic switch Q1 is controlled to turn on and off to realize the stepwise rising charging of the voltage of the electrolytic capacitor C1. When the electrolytic capacitor C1 completes charging, the sampling and driving circuit sends a signal to notify the motor microprocessor MCU that the electrolytic capacitor C1 has completed charging, and the motor can start. .

Preferably, the sampling and driving circuit includes a zero-crossing detection circuit and a sampling microprocessor MCU. The zero-crossing detection circuit is used to detect the zero-crossing signal of the alternating current and transmit the zero-crossing signal to the sampling microprocessor MCU. The sampling microprocessor The device MCU controls the on and off of the electronic switch Q1 to control the voltage of the electrolytic capacitor C1 to rise and charge in a stepwise manner.

Preferably, the stepwise rise charging of the voltage of electrolytic capacitor C1 uses a zero-crossing detection circuit to detect the zero-crossing signal of the alternating current, thereby knowing the period of the rectified half-wave output by the rectifier circuit, and charging the electrolytic capacitor in the period of N consecutive rectified half-waves. C1 intermittent charging forms a stepwise rise in voltage, and N is an integer.

Preferably, the period of the rectified half-wave is T, and the highest voltage point of a rectified half-wave period is in the middle of the rectified half-wave period T, that is, the charging time between the zero-crossing signal and the highest voltage point of the rectified half-wave period is T/2, the electrolytic capacitor C1 is intermittently charged during N consecutive rectification half-wave cycles. The intermittent charging time of each rectification half-wave cycle is T1. When the charging time reaches T1 in each rectification half-wave cycle, the microprocessor The MCU controls the electronic switch Q1 to open, so that the electrolytic capacitor C1 stops charging during the remaining period of the rectifier half-wave, and T1 is less than or equal to T/2.

Preferably, the electrolytic capacitor C1 is intermittently charged during N consecutive rectifying half-wave cycles to form a stepwise rise in voltage, and the starting time of charging the electrolytic capacitor C1 in the subsequent rectifying half-wave cycle is shorter than that in the previous rectifying half-wave cycle. The start time of charging electrolytic capacitor C1 is delayed by T1.

Preferably, when the intermittent charging of the electrolytic capacitor C1 is completed within the period of N consecutive rectification half-waves, that is, when the cumulative charging time of the electrolytic capacitor C1 reaches T/2 during the Nth rectification half-wave cycle, the electrolytic capacitor C1 is deemed to be completed. Charging can start the motor.

Preferably, the electronic switch Q1 is a triode, a field effect transistor, a MOS, a transistor, an IGBT, a thyristor, an SCR, or a relay.

Preferably, the voltage Udc across the electrolytic capacitor C1 is detected by a bus voltage detection circuit and sent to the sampling microprocessor MCU. The sampling microprocessor MCU compares the voltage Udc across the electrolytic capacitor C1 with the first set voltage value U1, When Udc is greater than or equal to U1, the electrolytic capacitor C1 is deemed to be fully charged and the motor can be started.

Another object of the present invention is to provide a soft start method for a permanent magnet motor system. The permanent magnet motor system adopts the above-mentioned permanent magnet motor system. The soft start method is as follows:

When the motor is powered on and started, the motor microprocessor MCU does not output a signal to the inverter circuit, and the inverter circuit stops working; the sampling and driving circuit is used to sample the externally input AC synchronization signal, and analyze and process the externally input AC synchronization signal. Afterwards, the electronic switch Q1 is controlled to turn on and off to realize the stepwise rising charging of the voltage of the electrolytic capacitor C1. When the electrolytic capacitor C1 completes charging, the sampling and driving circuit sends a signal to notify the motor microprocessor MCU that the electrolytic capacitor C1 has completed charging, and the motor can start. , the motor microprocessor MCU outputs a signal to the inverter circuit, controls the inverter circuit to drive the motor unit to operate, and the motor microprocessor MCU notifies the sampling and driving circuit to turn off the electronic switch Q1.

Preferably, the sampling and driving circuit includes a zero-crossing detection circuit and a sampling microprocessor MCU. The zero-crossing detection circuit is used to detect the zero-crossing signal of the alternating current and transmit the zero-crossing signal to the sampling microprocessor MCU. The sampling microprocessor MCU Thus, the period of the rectified half-wave output by the rectifier circuit is known, and then the electrolytic capacitor C1 is intermittently charged during the period of N consecutive rectified half-waves to form a stepwise rise in voltage.

Preferably, the electrolytic capacitor C1 is intermittently charged during N consecutive rectification half-wave cycles. The intermittent charging time of each rectification half-wave cycle is T1. When the charging time reaches T1 in each rectification half-wave cycle, the microprocessor The MCU controls the electronic switch Q1 to open, so that the electrolytic capacitor C1 stops charging during the remaining period of the rectified half-wave; the electrolytic capacitor C1 is intermittently charged during the N rectified half-wave periods to form a stepwise rise in voltage, and then the voltage rises in the final rectified half-wave period. The starting time of charging the electrolytic capacitor C1 in the cycle of the wave is delayed by T1 from the starting time of charging the electrolytic capacitor C1 in the cycle of the previous rectifying half wave.

Compared with the prior art, the present invention has the following effects:

1) The present invention provides a permanent magnet motor system that samples the externally input alternating current synchronization signal through a sampling and driving circuit, analyzes and processes the externally input alternating current synchronization signal, and then controls the on/off of the electronic switch Q1 to realize the switching of the electrolytic capacitor C1. The voltage rises and charges in a stepped manner. When the electrolytic capacitor C1 completes charging, the sampling and driving circuit sends a signal to the motor microprocessor MCU to notify the motor microprocessor MCU that the electrolytic capacitor C1 has completed charging. The motor can start, using multiple rectification half-wave cycles. Superimposing the electrolytic capacitor C1 to form a stepped charge can reduce the impact current when the mains is switched on and off to reduce the impact on the power grid, reduce the impact on the electrical components in the motor, and avoid damage to the electrical components. Moreover, the permanent magnet provided by this solution The motor system does not need to use the thermistor or resistor parallel relay circuit structure as the motor's soft start circuit, which can avoid the adverse effects caused by the thermistor or resistor parallel relay circuit structure, thereby better improving the motor's soft start circuit. reliability.

2) Other advantages of the present invention are described in detail in the embodiment section.

Description of the drawings

Figure 1 is a schematic diagram of a motor soft-start circuit using a thermistor circuit structure provided for the prior art;

Figure 2 is a schematic diagram of a motor soft start circuit using a resistor parallel relay circuit structure provided for the prior art;

Figure 3 is a schematic three-dimensional structural diagram of a permanent magnet motor provided for Embodiment 1 of the present invention;

Figure 4 is a schematic three-dimensional structural diagram of a motor controller provided for Embodiment 1 of the present invention;

Figure 5 is a schematic cross-sectional structural diagram of a permanent magnet motor provided for Embodiment 1 of the present invention;

Figure 6 is a circuit block diagram of a permanent magnet motor system provided for Embodiment 1 of the present invention;

Figure 7 is a schematic circuit structure diagram of a permanent magnet motor system provided for Embodiment 1 of the present invention;

Figure 8 is a schematic diagram of another circuit structure of the permanent magnet motor system provided for Embodiment 1 of the present invention;

Figure 9 is a schematic diagram illustrating the intermittent charging principle of an electrolytic capacitor provided in Embodiment 1 of the present invention;

Figure 10 is a schematic diagram of the voltage change of the electrolytic capacitor provided for Figure 9;

Figure 11 is an actual schematic diagram of the electrolytic capacitor provided for intermittent charging according to Embodiment 1 of the present invention;

Figure 12 is a schematic diagram of the voltage change of the electrolytic capacitor provided for Figure 11;

Figure 13 is a schematic diagram of the cycle charge and discharge principle of a single rectified half-wave of the permanent magnet motor system provided in Embodiment 1 of the present invention;

Figure 14 is a schematic diagram of the periodic charging and discharging principle of two consecutive rectified half-waves in the permanent magnet motor system provided for Embodiment 1 of the present invention;

Figure 15 is a circuit block diagram of a permanent magnet motor system provided for Embodiment 3 of the present invention.

Detailed ways

The present invention will be described in further detail below through specific embodiments and in conjunction with the accompanying drawings.

Example 1:

As shown in Figures 3 to 8, this embodiment provides a permanent magnet motor system, which includes a motor unit and a motor controller. The motor unit 1 includes a stator assembly 11 and a rotor assembly 12. The rotor assembly 12 is mounted on the stator. Inside or outside the component 11, the controller 2 includes a control box 22 and a control circuit board 21 installed inside the control box 22. The control circuit board integrates a power supply circuit, a motor microprocessor MCU, an inverter circuit and a position detection circuit. (i.e. Hall sensor), the power supply circuit supplies power to each part of the circuit, the motor microprocessor MCU controls the inverter circuit, and the inverter circuit controls the on and off of each phase coil winding of the stator assembly 11 to realize the start and stop of the motor alone. Control, position detection circuit (i.e. Hall sensor) is used to transmit the real-time operating parameters of the motor unit to the motor microprocessor MCU; the power supply circuit includes a filter circuit, a rectifier circuit, an electrolytic capacitor C1 and a discharge resistor R1, and the external input The alternating current is processed by the filter circuit and the rectifier circuit to charge the electrolytic capacitor C1. The voltage output terminal A of the rectifier circuit is connected to one end of the electrolytic capacitor C1, and the discharge resistor R1 is connected in parallel to both ends of the electrolytic capacitor C1.

As shown in Figures 6 to 8, the motor controller also includes a sampling and driving circuit and an electronic switch Q1. One end of the discharge resistor R1 is electrically connected to the voltage output terminal A of the rectifier circuit, and the other end is connected to the ground through the electronic switch Q1. The electronic switch The control terminal of Q1 is electrically connected to the signal output terminal of the sampling and driving circuit; the motor is powered on and starts, the motor microprocessor MCU does not output a signal to the inverter circuit, and the inverter circuit stops working. The sampling and driving circuit is used to sample the external input AC power. The synchronization signal of the external AC power is analyzed and processed, and then the electronic switch Q1 is controlled to turn on and off to realize the stepwise rise charging of the voltage of the electrolytic capacitor C1. When the electrolytic capacitor C1 completes charging, the sampling and driving circuit sends a signal Notify the motor microprocessor MCU that the electrolytic capacitor C1 has completed charging, and the motor can be started, thereby achieving the purpose of intelligent soft start of the motor. Multiple rectifier half-wave cycles are used to superimpose the electrolytic capacitor C1 to form a stepped charge, which can reduce the voltage when the mains is switched on and off. Inrush current is often used to reduce the impact on the power grid. Moreover, the permanent magnet motor system provided by this solution does not need to use the thermistor or resistor parallel relay circuit structure as the soft start circuit of the motor, which can avoid the thermistor or resistor parallel relay circuit. structure, thereby better improving the reliability of the soft-start circuit of the motor; in addition, in this embodiment, the sampling microprocessor MCU controls the on-off of the electronic switch Q1 through PWM. When the sampling microprocessor When the MCU stops sending PWM signals to the control electronic switch Q1, the electronic switch Q1 closes and the electrolytic capacitor C1 starts charging; when the sampling microprocessor MCU sends a PWM signal to the control electronic switch Q1, the electronic switch Q1 opens and the electrolytic capacitor C1 stops charging. By using PWM to control the on-off of electronic switch Q1, during use, the duty cycle or frequency of PWM can be adjusted according to different AC input voltages to change the charging time of electrolytic capacitor C1.

As shown in Figures 9 and 12, the sampling and driving circuit includes a zero-crossing detection circuit and a sampling microprocessor MCU. The zero-crossing detection circuit is used to detect the zero-crossing signal of the alternating current and transmit the zero-crossing signal to the sampling microprocessor. The sampling microprocessor MCU controls the on-off of the electronic switch Q1 to control the stepwise rising charging of the voltage of the electrolytic capacitor C1; specifically, the stepwise rising charging of the voltage of the electrolytic capacitor C1 is detected by a zero-crossing detection circuit. The zero-crossing signal of the alternating current is used to know the period of the rectified half-wave output by the rectifier circuit. The electrolytic capacitor C1 is intermittently charged during the period of N consecutive rectified half-waves to form a stepwise rise in voltage. N is an integer; the process in this embodiment is The zero detection circuit is a commonly used zero-crossing detection circuit in the prior art and will not be described in detail here.

As shown in Figures 9 to 14, more specifically, the period of the rectified half-wave is T, and the highest voltage point of a rectified half-wave cycle is in the middle of the rectified half-wave period T, that is, the zero-crossing signal and the rectified half-wave period are The charging time at the highest voltage point of the wave cycle is T/2. The electrolytic capacitor C1 is charged intermittently during N consecutive rectifying half-wave cycles. The intermittent charging time of each rectifying half-wave cycle is T1. When each rectifying half-wave cycle When the charging time reaches T1 in the cycle of the wave, the microprocessor MCU controls the electronic switch Q1 to open, so that the electrolytic capacitor C1 stops charging in the remaining cycle of the rectified half-wave, T1 is less than or equal to T/2; N consecutive rectified half-waves The intermittent charging of the electrolytic capacitor C1 during the period forms a stepwise rise in voltage. The starting time of charging the electrolytic capacitor C1 in the subsequent rectifying half-wave period is shorter than the starting time of charging the electrolytic capacitor C1 in the previous rectifying half-wave period. Delay T1, when the intermittent charging of electrolytic capacitor C1 is completed in the Nth rectification half-wave cycle, that is, when the cumulative charging time of electrolytic capacitor C1 in the N-th rectification half-wave cycle reaches T/2, it is regarded as electrolytic capacitor C1 After charging is completed, the motor can be started.

For example: Assume that the intermittent charging time T1 of each rectifying half-wave cycle is equal, that is, T1 is equal to T/2N, that is, the charging start time of electrolytic capacitor C1 in the subsequent rectifying half-wave cycle is longer than that of the previous rectifying half-wave cycle. The start time of charging electrolytic capacitor C1 in the cycle is delayed by T/2N; specifically, the start time of intermittent charging of electrolytic capacitor C1 in the first rectification half-wave cycle is from the zero crossing point to the end of T/2N. When When the charging time reaches T/2N in the first rectification half-wave cycle, the microprocessor MCU controls the electronic switch Q1 to open, causing the electrolytic capacitor C1 to stop charging in the remaining cycle of the first rectification half-wave. The starting time of intermittent charging of electrolytic capacitor C1 during the rectification half-wave cycle is from T/2N to the end of 2T/2N. When the charging time reaches T/2N during the second rectification half-wave cycle, the microprocessor MCU The electronic switch Q1 is controlled to open, so that the electrolytic capacitor C1 stops charging in the remaining period of the second rectification half-wave, and so on, until the starting time of intermittent charging of the electrolytic capacitor C1 in the N-th rectification half-wave period is Starting from (N-1)T/2N and ending with NT/2N, at this time, the cumulative charging time of electrolytic capacitor C1 reaches T/2 in the period of N consecutive rectifier half-waves. It is deemed that the charging of electrolytic capacitor C1 is completed, and the sampling micro The processor MCU no longer outputs a signal to close the electronic switch Q1, and the motor microprocessor MCU starts to start the motor unit; of course, in actual control, the intermittent charging time T1 of each rectification half-wave cycle can be adapted according to the rectification half-wave cycle. Adjustment, that is, the intermittent charging time T1 of each rectification half-wave cycle can be unequal.

The electronic switch Q1 is a triode, a field effect transistor MOS, a transistor IGBT, a thyristor SCR, or a relay.

It should be noted that when the charging time reaches T1 in each rectification half-wave cycle, the sampling microprocessor MCU controls the electronic switch Q1 to open, so that the electrolytic capacitor C1 stops charging and discharges in the remaining cycle of the rectification half-wave. There is a discharge process between the resistor R1 and the electrolytic capacitor C1. However, due to the small resistance of the discharge resistor R1 and the short period of each rectified half-wave, the discharge process can only discharge with an extremely weak current each time, so it is not possible. It will affect the voltage of electrolytic capacitor C1 after each charge, so that the voltage of electrolytic capacitor C1 can still be charged in a stepwise manner.

Example 2:

This embodiment provides a soft start method for a permanent magnet motor system. The permanent magnet motor system adopts the permanent magnet motor system described in the first embodiment. The soft start method is as follows:

The sampling and driving circuit includes a zero-crossing detection circuit and a sampling microprocessor MCU. The zero-crossing detection circuit is used to detect the zero-crossing signal of the alternating current and transmit the zero-crossing signal to the sampling microprocessor MCU. The sampling microprocessor MCU thus learns the rectification The circuit outputs a rectified half-wave cycle, and then intermittently charges the electrolytic capacitor C1 during N consecutive rectified half-wave cycles to form a stepwise rise in voltage.

The electrolytic capacitor C1 is intermittently charged during N consecutive rectification half-wave cycles. The intermittent charging time of each rectification half-wave cycle is T1. When the charging time reaches T1 in each rectification half-wave cycle, the microprocessor MCU controls the The electronic switch Q1 is turned on, causing the electrolytic capacitor C1 to stop charging during the remaining rectification half-wave cycle; the electrolytic capacitor C1 is intermittently charged during N consecutive rectification half-wave cycles to form a stepwise rise in voltage, and the final rectification half-wave cycle The start time of charging the electrolytic capacitor C1 is delayed by T1 from the start time of charging the electrolytic capacitor C1 in the previous rectification half-wave period.

Embodiment three:

This embodiment is based on Embodiment 1 and Embodiment 2, and improves the soft starting method of the permanent magnet motor system. As shown in Figure 15, in this embodiment, the voltage Udc across the electrolytic capacitor C1 is The bus voltage detection circuit detects and sends it to the sampling microprocessor MCU. The sampling microprocessor MCU compares the voltage Udc across the electrolytic capacitor C1 with the first set voltage value U1. When Udc is greater than or equal to U1, it is regarded as the electrolytic capacitor C1. After charging is completed, the motor can be started. By detecting the voltage Udc across the electrolytic capacitor C1, the soft start control can be made more precise.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited thereto. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention are all equivalent. All substitution methods are included in the protection scope of the present invention.

Claims

A permanent magnet motor system includes a motor unit and a motor controller. The motor unit includes a rotor assembly and a stator assembly. The motor controller includes a power supply circuit, a motor microprocessor MCU and an inverter circuit. The power supply circuit is each part. The circuit supplies power, and the motor microprocessor MCU controls the operation of the motor unit through the inverter circuit;

The power supply circuit includes a filter circuit, a rectifier circuit, an electrolytic capacitor C1 and a discharge resistor R1. The externally input alternating current is processed by the filter circuit and the rectifier circuit to charge the electrolytic capacitor C1. The voltage output terminal A of the rectifier circuit is connected to one end of the electrolytic capacitor C1. , the discharge resistor R1 is connected in parallel to both ends of the electrolytic capacitor C1;

It is characterized in that: the motor controller also includes a sampling and driving circuit and an electronic switch Q1. One end of the discharge resistor R1 is electrically connected to the voltage output terminal A of the rectifier circuit, and the other end is connected to the ground through the electronic switch Q1. The control terminal of the electronic switch Q1 is connected to the ground. The signal output terminals of the sampling and driving circuits are electrically connected;

When the motor is powered on and started, the motor microprocessor MCU does not output a signal to the inverter circuit, and the inverter circuit stops working. The sampling and driving circuit is used to sample the externally input AC synchronization signal, and analyze and process the externally input AC synchronization signal. Afterwards, the electronic switch Q1 is controlled to turn on and off to realize the stepwise rising charging of the voltage of the electrolytic capacitor C1. When the electrolytic capacitor C1 completes charging, the sampling and driving circuit sends a signal to notify the motor microprocessor MCU that the electrolytic capacitor C1 has completed charging, and the motor can start. .
A permanent magnet motor system according to claim 1, characterized in that: the sampling and driving circuit includes a zero-crossing detection circuit and a sampling microprocessor MCU, and the zero-crossing detection circuit is used to detect the zero-crossing signal of the alternating current, and The zero-crossing signal is sent to the sampling microprocessor MCU, and the sampling microprocessor MCU controls the on and off of the electronic switch Q1 to control the voltage of the electrolytic capacitor C1 to rise in a stepwise manner.
A permanent magnet motor system according to claim 2, characterized in that: the stepwise rise charging of the voltage of the electrolytic capacitor C1 uses a zero-crossing detection circuit to detect the zero-crossing signal of the alternating current, thereby knowing the rectified half-wave output of the rectifier circuit. Period, the electrolytic capacitor C1 is intermittently charged during a period of N consecutive rectification half-waves to form a stepwise rise in voltage, N is an integer.
A permanent magnet motor system according to claim 3, characterized in that: the period of the rectified half-wave is T, and the highest voltage point of a rectified half-wave period is at the middle position of the rectified half-wave period T, that is, zero crossing The charging time at the highest voltage point of the signal and the rectified half-wave cycle is T/2. The electrolytic capacitor C1 is charged intermittently during N consecutive rectified half-wave cycles. The intermittent charging time of each rectified half-wave cycle is T1. When The charging time reaches T1 in each rectification half-wave cycle, and the microprocessor MCU controls the electronic switch Q1 to open, so that the electrolytic capacitor C1 stops charging in the remaining cycle of the rectification half-wave, and T1 is less than or equal to T/2.
A permanent magnet motor system according to claim 4, characterized in that: the electrolytic capacitor C1 is intermittently charged during N consecutive rectifying half-wave cycles to form a stepwise rise in voltage, and the electrolytic capacitor C1 is charged intermittently during the last rectifying half-wave cycle. The starting time of charging C1 is delayed by T1 from the starting time of charging electrolytic capacitor C1 in the previous rectification half-wave cycle.
A permanent magnet motor system according to claim 5, characterized in that: when the intermittent charging of the electrolytic capacitor C1 is completed within the period of N consecutive rectification half-waves, that is, the electrolytic capacitor C1 is charged during the Nth rectification half-wave period. When the cumulative charging time reaches T/2, the electrolytic capacitor C1 is deemed to be fully charged and the motor can be started.
A permanent magnet motor system according to any one of claims 1 to 6, characterized in that the electronic switch Q1 is a triode, a field effect transistor MOS, a transistor IGBT, a thyristor SCR, or a relay.
A permanent magnet motor system according to any one of claims 1 to 3, characterized in that: the voltage Udc at both ends of the electrolytic capacitor C1 is detected by a bus voltage detection circuit and sent to the sampling microprocessor MCU, and the sampling microprocessor The MCU compares the voltage Udc across the electrolytic capacitor C1 with the first set voltage value U1. When Udc is greater than or equal to U1, the electrolytic capacitor C1 is deemed to be fully charged and the motor can be started.
A soft start method of a permanent magnet motor system, the permanent magnet motor system adopts the permanent magnet motor system described in any one of claims 1 to 8, characterized in that: the soft start method is as follows:

When the motor is powered on and started, the motor microprocessor MCU does not output a signal to the inverter circuit, and the inverter circuit stops working; the sampling and driving circuit is used to sample the externally input AC synchronization signal, and analyze and process the externally input AC synchronization signal. Afterwards, the electronic switch Q1 is controlled to turn on and off to realize the stepwise rising charging of the voltage of the electrolytic capacitor C1. When the electrolytic capacitor C1 completes charging, the sampling and driving circuit sends a signal to notify the motor microprocessor MCU that the electrolytic capacitor C1 has completed charging, and the motor can start. , the motor microprocessor MCU outputs a signal to the inverter circuit, controls the inverter circuit to drive the motor unit to operate, and the motor microprocessor MCU notifies the sampling and driving circuit to turn off the electronic switch Q1.
A soft start method for a permanent magnet motor system according to claim 9, characterized in that: the sampling and driving circuit includes a zero-crossing detection circuit and a sampling microprocessor MCU, and the zero-crossing detection circuit is used to detect the zero-crossing signal of the alternating current. , and transmits the zero-crossing signal to the sampling microprocessor MCU. The sampling microprocessor MCU thus learns the period of the rectified half-wave output by the rectifier circuit, and then intermittently charges the electrolytic capacitor C1 to form a voltage during N consecutive rectified half-wave periods. Step up.
A soft start method for a permanent magnet motor system according to claim 10, characterized in that: the electrolytic capacitor C1 is intermittently charged during N consecutive rectification half-wave cycles, and the intermittent charging time of each rectification half-wave cycle is T1, when the charging time reaches T1 in each rectification half-wave cycle, the microprocessor MCU controls the electronic switch Q1 to open, so that the electrolytic capacitor C1 stops charging in the remaining cycle of the rectification half-wave; N consecutive rectification half-waves The intermittent charging of the electrolytic capacitor C1 during the period forms a stepwise rise in voltage. The starting time of charging the electrolytic capacitor C1 in the subsequent rectifying half-wave period is shorter than the starting time of charging the electrolytic capacitor C1 in the previous rectifying half-wave period. Delay T1.