PMSM global protection system and method based on minimum signal detection

Abstract

The present invention discloses a global full-domain protection system and method for permanent magnet synchronous motors based on minimum signal detection. It includes a temperature sensor at a three-phase inverter, a current sensor and a voltage sensor on a bus between a rectifier circuit and a three-phase inverter; the temperature sensor collects the IGBT temperature in the three-phase inverter to trigger over-temperature protection; the voltage sensor collects the bus voltage to trigger undervoltage protection, overvoltage protection, and input phase loss protection; the current sensor collects the bus current to trigger overcurrent protection; the bus voltage and bus current are combined to trigger stall protection, stall protection, motor phase loss protection, overload protection, and motor body over-temperature protection. The present invention only collects the three sensor signals of bus voltage, bus current, and IGBT temperature to achieve global full-domain protection of the permanent magnet synchronous motor control system, which greatly reduces the manufacturing cost while also enhancing the robustness of the control system and reducing the possibility of fault false alarm shutdown due to sensor misalignment.

Description

Technical Field

[0001] The present invention relates to a permanent magnet synchronous motor protection system and method, and in particular to a permanent magnet synchronous motor (PMSM) global full-domain protection system and method based on minimum signal detection. Background Art

[0002] Permanent magnet synchronous motors are widely used in various industries due to their high efficiency. However, once a motor fails, it will cause great economic losses and even seriously threaten people's lives in some specific situations. Therefore, it is particularly important to protect the motor globally.

[0003] Motor fault protection generally includes under / overvoltage protection, input / motor phase loss protection, overload protection, overcurrent protection, stall protection, jam protection, overtemperature protection, etc.

[0004] In order to accurately obtain the motor's operating status, the motor needs to be equipped with various sensors to provide timely protection when the motor fails. The traditional permanent magnet synchronous motor signal acquisition system includes three-phase current sensors, voltage sensors, IGBT temperature sensors, motor body temperature sensors, position sensors, Hall elements, etc. The specific sensor layout and signal acquisition scheme are as follows: Figure 1 And as shown in Table 1.

[0005] Table 1 Signal acquisition scheme for traditional permanent magnet synchronous motor safety protection system

[0006]

[0007] Figure 1 In the figure, numbers 1, 2, and 3 are the current sensors that collect the three-phase current i in real time. a 、i b 、i c Signal collection point; No. 4 is the motor body temperature sensor to collect the motor temperature T in real time 1 Signal collection point; No. 5 is the input detection circuit to collect the input AC voltage U in real time ac Signal collection point; No. 6 is the voltage sensor that collects the bus voltage U in real time dc Signal collection point; No. 7 is the temperature sensor to collect the IGBT temperature T in real time 2 After being collected, all signals are sent to the controller for processing to determine what kind of fault the motor has and whether it can run reliably.

[0008] Therefore, traditional permanent magnet synchronous motor control systems require the use of a large number of sensors to effectively protect the motor, but this method is too expensive and the use of too many sensors can easily reduce the robustness of the system.

[0009] The disadvantages of the existing technology include:

[0010] (1) A large number of sensors are required, a lot of signal sampling, and high cost;

[0011] (2) Sensors are precision devices that are easily damaged and have a high failure rate;

[0012] (3) The system is complex, occupies a large volume, and has low robustness;

[0013] (4) In some special occasions where it is inconvenient to install sensors, it cannot be effectively promoted and applied;

[0014] (5) It is impossible to effectively achieve global and global protection, and the coverage is low. Summary of the invention

[0015] In order to solve the problems existing in the background technology, the present invention provides a global full-domain protection system and method for a permanent magnet synchronous motor based on minimum signal detection.

[0016] The technical solution adopted by the present invention is:

[0017] 1. A global protection system for PMSM based on minimum signal detection:

[0018] It includes a temperature sensor arranged at a three-phase inverter;

[0019] It includes a voltage sensor arranged on a busbar between a rectifier circuit and a three-phase inverter;

[0020] The utility model comprises a current sensor arranged on a bus bar between a rectifier circuit and a three-phase inverter.

[0021] The system is only provided with the temperature sensor, voltage sensor and current sensor.

[0022] The temperature sensor, voltage sensor and current sensor are all connected to the controller.

[0023] The voltage sensor and the current sensor are arranged between the positive electrode of the bus capacitor and the three-phase inverter in the rectifier circuit.

[0024] 2. A global protection method for PMSM based on minimum signal detection:

[0025] The temperature sensor is used to collect the IGBT temperature T in the three-phase inverter in real time. ntc , collect bus voltage U in real time through voltage sensor dc , the bus current i is collected in real time through the current sensor dc , and then make the following judgment:

[0026] According to the bus voltage U collected by the voltage sensor dcDetermine whether the permanent magnet synchronous motor has overvoltage, undervoltage, or input phase loss faults, thereby triggering undervoltage protection, overvoltage protection, and input phase loss protection;

[0027] According to the bus current i collected by the current sensor dc Determine whether the permanent magnet synchronous motor has overcurrent, thereby triggering overcurrent protection;

[0028] The bus voltage U collected by the voltage sensor dc The bus current i collected by the current sensor dc Combined judgment is made to determine whether the permanent magnet synchronous motor has stall, stall, motor phase loss, overload, or motor body overtemperature faults, thereby triggering stall protection, stall protection, motor phase loss protection, overload protection, and motor body overtemperature protection;

[0029] The IGBT temperature T collected by the temperature sensor ntc It can identify whether the motor body is overheating, thereby accurately triggering the control overtemperature protection.

[0030] Therefore, by adopting the permanent magnet synchronous motor control system signal acquisition scheme and sensor layout scheme proposed in the present invention, global and full-domain protection of the motor can be achieved.

[0031] The motor body over-temperature protection is specifically as follows:

[0032] 1) The bus voltage U collected by the voltage sensor in real time dc After filtering, the data is transmitted to the controller for data processing;

[0033] 2) Three-phase voltage reconstruction: The PWM control signal from the controller is combined with the bus voltage U dc Combined processing to obtain the three-phase voltage U a , U b , U c ;

[0034] 3) The bus current i collected by the current sensor in real time dc After filtering, the data is transmitted to the controller for data processing;

[0035] 4) Three-phase current reconstruction: The PWM control signal from the controller is combined with the bus current i dc Combined processing to obtain the three-phase current i a 、i b 、i c ;

[0036] 5) According to the three-phase voltage U a , U b , U c and three-phase current i a 、i b 、ic Use Ohm's law to get the real-time calculated resistance R of the three-phase windings a , R b , R c ;

[0037] 6) The real-time calculated resistance value R of the three-phase winding a , R b , R c Substitute the following resistance temperature rise formulas to obtain the real-time temperature of each phase winding:

[0038]

[0039] Where, T nml is the temperature of a phase winding at room temperature; T ntc is the temperature sent back by the temperature sensor before the permanent magnet synchronous motor starts; R nml is the resistance of a phase winding at room temperature; R is the real-time resistance of a phase winding; T is the real-time temperature of a phase winding;

[0040] 7) The real-time temperature values ​​of the three-phase windings are averaged to obtain the average temperature T of the three-phase windings, and the average temperature T of the three-phase windings is compared with the preset temperature threshold T * For comparison:

[0041] If the average temperature T of the three-phase winding is less than the temperature threshold T * , then the undervoltage protection will not be triggered;

[0042] If the average temperature T of the three-phase winding is greater than or equal to the temperature threshold T * , the motor body over-temperature protection is triggered, and the permanent magnet synchronous motor system is controlled to alarm and shut down.

[0043] The under / over voltage protection is as follows:

[0044] The voltage sensor collects the bus voltage U in real time dc After filtering, the data is transmitted to the controller for data processing, and is compared with the preset bus voltage undervoltage threshold and bus voltage overvoltage threshold in real time:

[0045] A) The bus voltage U dc Compare with the preset bus voltage undervoltage threshold:

[0046] If the bus voltage U dc If the voltage is lower than the bus voltage undervoltage threshold, the undervoltage protection will not be triggered;

[0047] If the bus voltage U dc If the bus voltage is greater than or equal to the bus voltage undervoltage threshold, then the bus voltage U dc Whether the duration of the bus voltage continuously being greater than or equal to the undervoltage threshold reaches the preset undervoltage protection time t 1 :

[0048] If the undervoltage protection time t is not reached 1 , then the undervoltage protection will not be triggered;

[0049] If the undervoltage protection time t is reached 1 , the undervoltage protection is triggered and the permanent magnet synchronous motor system is controlled to alarm and shut down.

[0050] B) The bus voltage U dc Compare with the preset bus voltage overvoltage threshold:

[0051] If the bus voltage U dc If it is less than the bus voltage overvoltage threshold, the undervoltage protection will not be triggered;

[0052] If the bus voltage U dc If the bus voltage is greater than or equal to the bus voltage overvoltage threshold, then the bus voltage U dc Whether the duration of the bus voltage continuously being greater than or equal to the bus voltage overvoltage threshold reaches the preset overvoltage protection time t 2 :

[0053] If the pre-overvoltage protection time t is not reached 2 , the overvoltage protection will not be triggered;

[0054] If the overvoltage protection time t is reached 2 , the overvoltage protection is triggered and the permanent magnet synchronous motor system is controlled to alarm and shut down.

[0055] The overcurrent protection is specifically as follows:

[0056] The bus current i collected by the current sensor in real time dc After filtering, the data is transmitted to the controller for data processing, and the bus current i dc Compare with preset bus current threshold:

[0057] If the bus current i dc If it is less than the bus current threshold, the overcurrent protection will not be triggered;

[0058] If the bus current i dc If it is greater than or equal to the bus current threshold, then the bus current i dc Whether the duration of the bus current threshold being continuously greater than or equal to the bus current threshold reaches the preset overvoltage protection time t 3 :

[0059] If the overvoltage protection time t is not reached 3 , the over-current protection will not be triggered;

[0060] If the overvoltage protection time t is reached 3 , the overcurrent protection is triggered and the permanent magnet synchronous motor system is controlled to alarm and shut down.

[0061] The present invention is a safety system that can achieve global protection of permanent magnet synchronous motors based on minimal signal acquisition. The key point is that only the three sensor signals of bus voltage, bus current and IGBT temperature need to be collected to achieve global protection of the motor. While greatly reducing the manufacturing cost, it also enhances the robustness of the control system and reduces the possibility of false alarms and shutdowns caused by sensor inaccuracy. Compared with the traditional permanent magnet synchronous motor signal acquisition solution, the present invention does not need to install any sensors on the motor body, and the real-time temperature of the motor body can be measured by the change of the three-phase winding resistance.

[0062] The beneficial effects of the present invention are:

[0063] The present invention can realize global full-domain protection of the permanent magnet synchronous motor control system by only collecting three signals: bus voltage, bus current and IGBT temperature.

[0064] The present invention effectively solves the above-mentioned defects by improving the signal acquisition method to reduce the use of sensors and utilizing the temperature rise effect of the three-phase winding to collect the temperature of the motor body. While greatly reducing the manufacturing cost, it can also provide global and full-domain protection for the reliable operation of the permanent magnet synchronous motor.

[0065] The present invention can achieve global and full-domain protection of the permanent magnet synchronous motor by using only one current sensor, one voltage sensor, and one IGBT temperature sensor. Compared with the complex signal acquisition system of the traditional permanent magnet synchronous motor, it greatly reduces the manufacturing cost while also enhancing the robustness of the system, and reduces the false alarm shutdown phenomenon of the motor caused by sensor inaccuracy or failure.

[0066] The present invention does not need to install any sensor on the motor body, which makes the present invention also applicable to some application occasions where it is not convenient to install sensors in the motor body, and effectively reduces the volume, which is conducive to the development of micro precision motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is the sensor layout diagram of the traditional permanent magnet synchronous motor control system;

[0068] Figure 2 It is a sensor layout structure diagram of a permanent magnet synchronous motor control system based on minimum signals of the present invention;

[0069] Figure 3 It is a schematic diagram of the global protection technology of the permanent magnet synchronous motor control system of the present invention;

[0070] Figure 4 This is a flow chart of over-temperature protection of the motor body of the present invention;

[0071] Figure 5 It is the under / overvoltage protection flow chart of the present invention;

[0072] Figure 6 It is the overcurrent protection flow chart of the present invention. DETAILED DESCRIPTION

[0073] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0074] like Figure 2 As shown, the system of the present invention is configured as follows:

[0075] It includes a temperature sensor arranged at a three-phase inverter;

[0076] It includes a voltage sensor arranged on a busbar between a rectifier circuit and a three-phase inverter;

[0077] The utility model comprises a current sensor arranged on a bus bar between a rectifier circuit and a three-phase inverter.

[0078] The system is only equipped with temperature sensors, voltage sensors and current sensors. No sensors are installed in other locations, nor are other types of sensors installed.

[0079] The temperature sensor, the voltage sensor, and the current sensor are all electrically connected to the controller.

[0080] The voltage sensor and the current sensor are arranged between the positive electrode of the bus capacitor and the three-phase inverter in the rectifier circuit.

[0081] The specific implementation of the permanent magnet synchronous motor system is as follows Figure 2 As shown, it includes a controller, a three-phase inverter, a permanent magnet synchronous motor PMSM and a rectifier circuit; the rectifier circuit is mainly composed of a parallel rectifier bridge and a bus capacitor. The external voltage is connected to the two-phase input end of the three-phase inverter through the rectifier circuit, the three-phase output end of the three-phase inverter is connected to the permanent magnet synchronous motor PMSM, and the controller is connected to the control end of the three-phase inverter.

[0082] like Figure 2 In the figure, the temperature sensor at number 1 collects the temperature T of the IGBT in the three-phase inverter in real time. 1 The signal collection point numbered 2 is the voltage sensor that collects the bus voltage U in real time. dc The signal collection point numbered 3 is the current sensor that collects the bus current i in real time. dc Signal collection point;

[0083] After all signal collection points collect signals, they are transmitted to the controller for processing to determine what kind of fault the permanent magnet synchronous motor has and whether it can operate reliably.

[0084] like Figure 2 and Figure 3 As shown in the figure, the global protection process is as follows:

[0085] The temperature sensor is used to collect the IGBT temperature T in the three-phase inverter in real time. ntc , collect bus voltage U in real time through voltage sensor dc , the bus current i is collected in real time through the current sensor dc , and then make the following judgment:

[0086] According to the bus voltage U collected by the voltage sensor dc Determine whether the permanent magnet synchronous motor has overvoltage, undervoltage, or input phase loss faults, thereby accurately triggering undervoltage protection, overvoltage protection, and input phase loss protection;

[0087] According to the bus current i collected by the current sensor dc Determine whether the permanent magnet synchronous motor has overcurrent, so as to accurately trigger and implement overcurrent protection;

[0088] The bus voltage U collected by the voltage sensor dc The bus current i collected by the current sensor dc Combined judgment is made on whether the permanent magnet synchronous motor has stall, stall, motor phase loss, overload, or motor body overtemperature faults, so as to accurately trigger stall protection, stall protection, motor phase loss protection, overload protection, and motor body overtemperature protection;

[0089] The IGBT temperature T collected by the temperature sensor ntc It can identify whether the motor body is overheating, thereby accurately triggering the control overtemperature protection.

[0090] In specific implementation, the three innovation protection processes are as follows:

[0091] like Figure 4 As shown in the figure, the motor body over-temperature protection process is as follows:

[0092] After the permanent magnet synchronous motor is powered on and enters the running state, it starts to perform real-time over-temperature detection of the motor body;

[0093] 1) The bus voltage U collected by the voltage sensor in real time dc After filtering, the data is transmitted to the controller for data processing;

[0094] 2) Three-phase voltage reconstruction: The PWM control signal from the controller is combined with the bus voltage U dc Combined processing to obtain the three-phase voltage U a , U b , U c ;

[0095] 3) The bus current i collected by the current sensor in real time dc After filtering, the data is transmitted to the controller for data processing;

[0096] 4) Three-phase current reconstruction: The PWM control signal from the controller is combined with the bus current i dc Combined processing to obtain the three-phase current i a 、i b 、i c ;

[0097] 5) According to the three-phase voltage U a , U b , U c and three-phase current i a 、i b 、i c Use Ohm's law to get the real-time calculated resistance R of the three-phase windings a , R b , R c ;

[0098] Ohm's law formula is as follows:

[0099]

[0100] In the formula, R is the resistance value, U is the voltage, and I is the current.

[0101] 6) The real-time calculated resistance value R of the three-phase winding a , R b , R c Substitute the following resistance temperature rise formulas to obtain the real-time temperature of each phase of the three-phase winding:

[0102]

[0103] Where, T nml is the temperature of a phase winding at room temperature; T ntc It is the temperature sent back by the temperature sensor before the permanent magnet synchronous motor starts, which is approximately equal to the initial temperature of one phase winding; R nml is the resistance of a phase winding at room temperature; R is the real-time resistance of a phase winding; T is the real-time temperature of a phase winding; the constant 235 is applicable to copper wire windings, while the constant is 225 for aluminum wire windings.

[0104] 7) The real-time temperature values ​​of the three-phase windings are averaged to obtain the average temperature T of the three-phase windings, and the average temperature T of the three-phase windings is compared with the preset temperature threshold T * For comparison:

[0105] If the average temperature T of the three-phase winding is less than the temperature threshold T * , then the undervoltage protection will not be triggered;

[0106] If the average temperature T of the three-phase winding is greater than or equal to the temperature threshold T * , the motor body over-temperature protection is triggered, and the permanent magnet synchronous motor system is controlled to alarm and shut down.

[0107] like Figure 5 As shown in the figure, the under / overvoltage protection process is as follows:

[0108] After the permanent magnet synchronous motor is powered on and enters the running state, it starts to perform under / overvoltage detection in real time;

[0109] The voltage sensor collects the bus voltage U in real time dc After filtering, the data is transmitted to the controller for data processing, and is compared with the preset bus voltage undervoltage threshold and bus voltage overvoltage threshold in real time:

[0110] A) The bus voltage U dc Compare with the preset bus voltage undervoltage threshold:

[0111] If the bus voltage U dc If the voltage is lower than the bus voltage undervoltage threshold, the undervoltage protection will not be triggered;

[0112] If the bus voltage U dc If the bus voltage is greater than or equal to the bus voltage undervoltage threshold, then the bus voltage U dc Whether the duration of the bus voltage continuously being greater than or equal to the undervoltage threshold reaches the preset undervoltage protection time t 1 :

[0113] If the undervoltage protection time t is not reached 1 , then the undervoltage protection will not be triggered;

[0114] If the undervoltage protection time t is reached 1 , the undervoltage protection is triggered and the permanent magnet synchronous motor system is controlled to alarm and shut down.

[0115] B) At the same time, the bus voltage U dc Compare with the preset bus voltage overvoltage threshold:

[0116] If the bus voltage U dc If it is less than the bus voltage overvoltage threshold, the undervoltage protection will not be triggered;

[0117] If the bus voltage U dc If the bus voltage is greater than or equal to the bus voltage overvoltage threshold, then the bus voltage U dc Whether the duration of the bus voltage continuously being greater than or equal to the bus voltage overvoltage threshold reaches the preset overvoltage protection time t 2 :

[0118] If the pre-overvoltage protection time t is not reached 2 , the overvoltage protection will not be triggered;

[0119] If the overvoltage protection time t is reached 2 , the overvoltage protection is triggered and the permanent magnet synchronous motor system is controlled to alarm and shut down.

[0120] like Figure 6 As shown in the figure, the overcurrent protection process is as follows:

[0121] After the permanent magnet synchronous motor is powered on and enters the running state, it starts to perform overcurrent detection in real time;

[0122] The bus current i collected by the current sensor in real time dc After filtering, the data is transmitted to the controller for data processing, and the bus current i dc Compare with preset bus current threshold:

[0123] If the bus current i dc If it is less than the bus current threshold, the overcurrent protection will not be triggered;

[0124] If the bus current i dc If it is greater than or equal to the bus current threshold, then the bus current i dc Whether the duration of the bus current threshold being continuously greater than or equal to the bus current threshold reaches the preset overvoltage protection time t 3 :

[0125] If the overvoltage protection time t is not reached 3 , the over-current protection will not be triggered;

[0126] If the overvoltage protection time t is reached 3 , the overcurrent protection is triggered and the permanent magnet synchronous motor system is controlled to alarm and shut down.

[0127] Through testing of the embodiments, the present invention can be widely applied to fan motors, has a wide speed regulation range, high speed accuracy, and can be promoted in batches.

Claims

1. A global protection method for PMSM based on minimum signal detection, characterized by: The method adopts a PMSM global global protection system, wherein the PMSM global global protection system includes only one temperature sensor disposed at a three-phase inverter; includes only one voltage sensor disposed on a bus between a rectifier circuit and a three-phase inverter; including only one current sensor disposed on a bus bar between a rectifier circuit and a three-phase inverter; The PMSM global protection system is only provided with the temperature sensor, voltage sensor and current sensor; The method uses a temperature sensor to collect the IGBT temperature T in the three-phase inverter in real time. ntc , collect bus voltage U in real time through voltage sensor dc , the bus current i is collected in real time through the current sensor dc , and then make the following judgment: According to the bus voltage U collected by the voltage sensor dc Determine whether the permanent magnet synchronous motor has overvoltage, undervoltage, or input phase loss faults, thereby triggering undervoltage protection, overvoltage protection, and input phase loss protection; According to the bus current i collected by the current sensor dc Determine whether the permanent magnet synchronous motor has overcurrent, thereby triggering overcurrent protection; The bus voltage U collected by the voltage sensor dc The bus current i collected by the current sensor dc Combined judgment is made to determine whether the permanent magnet synchronous motor has stall, stall, motor phase loss, overload, or motor body overtemperature faults, thereby triggering stall protection, stall protection, motor phase loss protection, overload protection, and motor body overtemperature protection; The IGBT temperature T collected by the temperature sensor ntc It can identify whether the motor body is overheated, thereby accurately triggering the control over-temperature protection; The motor body over-temperature protection is specifically as follows: 1) The bus voltage U collected by the voltage sensor in real time dc After filtering, the data is transmitted to the controller for data processing; 2) Three-phase voltage reconstruction: The PWM control signal from the controller is combined with the bus voltage U dc Combined processing to obtain the three-phase voltage U a , U b , U c ; 3) The bus current i collected by the current sensor in real time dc After filtering, the data is transmitted to the controller for data processing; 4) Three-phase current reconstruction: The PWM control signal from the controller is combined with the bus current i dc Combined processing to obtain the three-phase current i a 、i b 、i c ; 5) According to the three-phase voltage U a , U b , U c and three-phase current i a 、i b 、i c Use Ohm's law to get the real-time calculated resistance R of the three-phase windings a , R b , R c ; 6) The real-time calculated resistance value R of the three-phase winding a , R b , R c Substitute the following resistance temperature rise formulas to obtain the real-time temperature of each phase winding: Where, T nml is the temperature of a phase winding at room temperature; T ntc is the temperature sent back by the temperature sensor before the permanent magnet synchronous motor starts; R nml is the resistance of a phase winding at room temperature; R is the real-time resistance of a phase winding; T is the real-time temperature of a phase winding; 7) The real-time temperature values ​​of the three-phase windings are averaged to obtain the average temperature T of the three-phase windings, and the average temperature T of the three-phase windings is compared with the preset temperature threshold T * For comparison: If the average temperature T of the three-phase winding is less than the temperature threshold T * , the motor body over-temperature protection will not be triggered; If the average temperature T of the three-phase winding is greater than or equal to the temperature threshold T * , the motor body over-temperature protection is triggered, and the permanent magnet synchronous motor system is controlled to alarm and shut down.

2. The PMSM global protection method based on minimum signal detection according to claim 1 is characterized in that: The details of under / over voltage protection are as follows: The voltage sensor collects the bus voltage U in real time dc After filtering, the data is transmitted to the controller for data processing, and is compared with the preset bus voltage undervoltage threshold and bus voltage overvoltage threshold in real time: A) The bus voltage U dc Compare with the preset bus voltage undervoltage threshold: If the bus voltage U dc If the voltage is lower than the bus voltage undervoltage threshold, the undervoltage protection will not be triggered; If the bus voltage U dc If the bus voltage is greater than or equal to the bus voltage undervoltage threshold, then the bus voltage U dc Whether the duration of the bus voltage continuously being greater than or equal to the bus voltage undervoltage threshold reaches the preset undervoltage protection time t1: If the undervoltage protection time t1 is not reached, the undervoltage protection will not be triggered; If the undervoltage protection time t1 is reached, the undervoltage protection is triggered and the permanent magnet synchronous motor system is controlled to alarm and shut down; B) The bus voltage U dc Compare with the preset bus voltage overvoltage threshold: If the bus voltage U dc If it is less than the bus voltage overvoltage threshold, the undervoltage protection will not be triggered; If the bus voltage U dc If the bus voltage is greater than or equal to the bus voltage overvoltage threshold, then the bus voltage U dc Whether the duration of the bus voltage being continuously greater than or equal to the bus voltage overvoltage threshold reaches the preset overvoltage protection time t2: If the pre-overvoltage protection time t2 is not reached, the overvoltage protection will not be triggered; If the overvoltage protection time t2 is reached, the overvoltage protection is triggered and the permanent magnet synchronous motor system is controlled to alarm and shut down.

3. The PMSM global protection method based on minimum signal detection according to claim 1 is characterized in that: The overcurrent protection is specifically as follows: The bus current i collected by the current sensor in real time dc After filtering, the data is transmitted to the controller for data processing, and the bus current i dc Compare with preset bus current threshold: If the bus current i dc If it is less than the bus current threshold, the overcurrent protection will not be triggered; If the bus current i dc If it is greater than or equal to the bus current threshold, then the bus current i dc Whether the duration of the bus current threshold being continuously greater than or equal to the bus current threshold reaches the preset overvoltage protection time t3: If the overvoltage protection time t3 is not reached, the overcurrent protection will not be triggered; If the overvoltage protection time t3 is reached, the overcurrent protection is triggered and the permanent magnet synchronous motor system is controlled to alarm and shut down.

4. The PMSM global protection method based on minimum signal detection according to claim 1 is characterized in that: The temperature sensor, voltage sensor and current sensor are all connected to the controller.

5. The PMSM global protection method based on minimum signal detection according to claim 1 is characterized in that: The voltage sensor and the current sensor are arranged between the positive electrode of the bus capacitor and the three-phase inverter in the rectifier circuit.

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