Motor control circuit

Abstract

The invention relates to the technical field of motor control, and discloses a motor control circuit, the motor control circuit is connected with a power supply conversion module, the motor control circuit comprises a three-phase full-wave module, the input end of the three-phase full-wave module is connected with the power supply conversion module, and the three-phase full-wave module is used for collecting three-phase voltage signals transmitted by the power supply conversion module; rectifying the three-phase voltage signal to obtain a three-phase full-wave signal, and outputting the three-phase full-wave signal; the power failure protection module is connected with the output end of the three-phase full-wave module and used for receiving the three-phase full-wave signal and outputting a charging signal when it is detected that the three-phase full-wave signal is smaller than a preset switching value; and the rectification soft start module is internally provided with an energy storage unit, and the rectification soft start module is respectively connected with the power supply conversion module and the power failure protection module and is used for charging the energy storage unit after receiving the charging signal. The problem that in the prior art, when a capacitor of a motor is discharged to a low potential, large current is generated when the capacitor is charged again is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a motor control circuit. Background Art

[0002] With the development of motors, DC motors are widely used. Since most of the DC power supply of DC motors comes from the mains, it is basically obtained through mains rectification and capacitor filtering. The mains may cause power outages or power failures due to load overcurrent, line maintenance, environmental factors, etc. Some key equipment used in military, aviation, hospitals, banks, etc. are not allowed to be powered off. If a power outage or power failure occurs, it will cause immeasurable losses. Therefore, a backup power supply is used, and when a power outage or power failure occurs, it is switched to the backup power supply for operation.

[0003] When a DC motor is running under load and the grid loses power or a power outage occurs and the system switches to the backup power supply, the motor's filter capacitor will discharge to a low potential and then charge the electrolytic capacitor again, which will generate a large current. As a result, the line will overcurrent and the switch will trip to cut off the power. Summary of the invention

[0004] In view of this, the present invention provides a motor control circuit to solve the problem in the prior art that the capacitor of the motor is discharged to a low potential and a large current is generated when the capacitor is charged again.

[0005] In a first aspect, the present invention provides a motor control circuit, the motor control circuit is connected to a power conversion module, and the motor control circuit includes:

[0006] A three-phase full-wave module, the input end of the three-phase full-wave module is connected to the power conversion module, used to collect the three-phase voltage signal transmitted by the power conversion module, rectify the three-phase voltage signal to obtain a three-phase full-wave signal, and output the three-phase full-wave signal;

[0007] A power-off protection module is connected to the output end of the three-phase full-wave module and is used to receive a three-phase full-wave signal and output a charging signal when it is detected that the three-phase full-wave signal is less than a preset switching value;

[0008] The rectifier soft start module has a built-in energy storage unit. The rectifier soft start module is connected to the power conversion module and the power-off protection module respectively, and is used to charge the energy storage unit after receiving a charging signal.

[0009] In the motor control circuit provided by the present invention, a three-phase full-wave module receives a three-phase voltage signal and outputs a three-phase voltage signal, a power-off protection module outputs a charging signal when detecting that the three-phase voltage signal is less than a preset switching value, and a rectifier soft-start module charges an energy storage unit built into the rectifier soft-start module after receiving the charging signal, thereby charging the backup power supply when the power grid power supply is switched to the backup power supply, thereby preventing the energy storage unit from discharging to a low potential and generating a large current when charging again.

[0010] In an optional implementation, the rectifier soft start module includes:

[0011] A rectifier bridge, the input end of the rectifier bridge is connected to the power conversion module;

[0012] A relay, wherein a first control end of the relay is connected to an output end of the rectifier bridge, a second control end of the relay is connected to an energy storage unit, a first power supply end of the relay is connected to a preset reference voltage, a second power supply end of the relay is connected to a power-off protection module, and after receiving a charging signal, the second power supply end of the relay disconnects the connection between the rectifier bridge and the energy storage unit;

[0013] A first inductor, a first end of the first inductor is connected to a first control end of the relay, a second end of the first inductor is connected to a second control end of the relay, and when the relay disconnects the rectifier bridge and the energy storage unit, the energy storage unit is charged through the first inductor.

[0014] In an optional implementation, the rectifier soft start module includes:

[0015] A first diode, wherein a first end of the first diode is connected to a first power supply end of the relay, and a second end of the first diode is connected to a second power supply end of the relay.

[0016] In an optional implementation, the power-off protection module includes:

[0017] A first voltage stabilizing diode, wherein a first end of the first voltage stabilizing diode is connected to the three-phase full-wave module;

[0018] A first resistor, a first end of the first resistor is connected to a second end of the first voltage stabilizing diode;

[0019] A first switch tube, wherein a control end of the first switch tube is connected to a second end of the first resistor, a first end of the first switch tube is connected to a rectifier soft-start module, and a second end of the first switch tube is grounded;

[0020] Among them, the first switch tube is turned off when it is detected that the three-phase full-wave signal is less than a preset switching value, and a charging signal is output.

[0021] In an optional embodiment, the power-off protection module is connected to the fault protection module. When the fault protection module detects that the power-off protection module outputs a charging signal, the fault protection module transmits a shutdown signal to the motor drive module through the shutdown control module and the main control module, so that the motor drive module stops driving the motor.

[0022] In an optional embodiment, the circuit includes:

[0023] A voltage detection module, the voltage detection module is connected to the energy storage unit and the fault protection module respectively, and is used to output a start signal to the fault protection module when it is detected that the voltage of the energy storage unit is greater than a preset voltage value, wherein the start signal is transmitted to the main control module through the shutdown control module;

[0024] The power-off protection module also includes:

[0025] a second switch tube, wherein the control end of the second switch tube is connected to the main control module, the first end of the second switch tube is connected to the control end of the first switch tube, the second end of the second switch tube is grounded, and the second switch tube is closed after receiving the start signal to turn on the first switch tube, so that the first switch tube stops outputting the charging signal;

[0026] A second voltage stabilizing diode, wherein a first end of the second voltage stabilizing diode is connected to the control end of the first switch tube, and a second end of the second voltage stabilizing diode is grounded;

[0027] A first capacitor, wherein a first end of the first capacitor is connected to the control end of the first switch tube, and a second end of the first capacitor is grounded;

[0028] A second resistor, wherein a first end of the second resistor is connected to the control end of the first switch tube, and a second end of the second resistor is grounded.

[0029] In an optional implementation, the voltage detection module includes:

[0030] A comparator, wherein a first input terminal of the comparator is connected to the energy storage unit, an output terminal of the comparator is connected to the fault protection module, and when the comparator detects that the voltage of the energy storage unit is greater than a preset voltage value, the comparator outputs a start signal to the fault protection module;

[0031] a third resistor, wherein a first end of the third resistor is connected to a preset reference voltage, and a second end of the third resistor is connected to a second input end of the comparator;

[0032] a fourth resistor, wherein a first end of the fourth resistor is connected to a second end of the third resistor, and a second end of the fourth resistor is grounded;

[0033] a fifth resistor, wherein a first end of the fifth resistor is connected to a preset reference voltage, and a second end of the fifth resistor is connected to an output end of the comparator;

[0034] A clamping diode, a first end of the clamping diode is connected to the first input end of the comparator, a second end of the clamping diode is connected to a preset reference voltage, and a third end of the clamping diode is grounded.

[0035] In an optional embodiment, the three-phase full-wave module includes:

[0036] A second diode, wherein a first end of the second diode is connected to the A-phase power supply end of the power conversion module, and a second end of the second diode is connected to the power-off protection module;

[0037] A third diode, wherein a first end of the third diode is connected to the B-phase power supply end of the power conversion module, and a second end of the third diode is connected to the power-off protection module;

[0038] A fourth diode, wherein a first end of the fourth diode is connected to the C-phase power supply end of the power conversion module, and a second end of the fourth diode is connected to the power-off protection module.

[0039] In an optional embodiment, the circuit includes:

[0040] An input filter module, wherein the first end of the input filter module is connected to the power conversion module, and the second end of the input filter module is respectively connected to the rectifier soft start module and the three-phase full-wave module. The input filter module is used to filter the three-phase voltage signal transmitted by the power conversion module, and transmit the filtered three-phase voltage signal to the rectifier soft start module and the three-phase full-wave module respectively.

[0041] In an optional implementation, the input filtering module includes:

[0042] An A-phase filter unit consisting of a second capacitor, a sixth resistor and a second inductor, wherein the second capacitor is connected in parallel with the sixth resistor;

[0043] A B-phase filter unit consisting of a third capacitor, a seventh resistor and a third inductor, wherein the third capacitor is connected in parallel with the seventh resistor;

[0044] A C-phase filter unit consisting of a fourth capacitor, an eighth resistor and a fourth inductor, wherein the fourth capacitor is connected in parallel with the eighth resistor.

[0045] In an optional embodiment, the circuit includes:

[0046] The discharge module is connected to the three-phase full-wave module and the power-off protection module respectively, and releases the residual voltage of the second capacitor, the third capacitor and the fourth capacitor when detecting that the power-off protection module sends a charging signal.

[0047] In an optional embodiment, the discharge module includes:

[0048] A ninth resistor, wherein a first end of the ninth resistor is connected to the rectifier soft start module;

[0049] A third switch tube, wherein a control end of the third switch tube is connected to the second end of the ninth resistor, and a first end of the third switch tube is grounded;

[0050] a tenth resistor, wherein a first end of the tenth resistor is connected to the control end of the third switch tube, and a second end of the tenth resistor is grounded;

[0051] An eleventh resistor, a first end of the eleventh resistor is connected to the three-phase full-wave module, and a second end of the eleventh resistor is connected to the second end of the third switch tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 It is a conventional motor control circuit;

[0054] Figure 2 is a structural diagram of a motor control circuit according to an embodiment of the present invention;

[0055] Figure 3 is a detailed structural diagram of a rectifier soft start module in a motor control circuit according to an embodiment of the present invention;

[0056] Figure 4 is a detailed structural diagram of a power-off protection module in a motor control circuit according to an embodiment of the present invention;

[0057] Figure 5 is a detailed structural diagram of a voltage detection module in a motor control circuit according to an embodiment of the present invention;

[0058] Figure 6 is a structural diagram of another motor control circuit according to an embodiment of the present invention;

[0059] Figure 7 It is a voltage curve diagram of a conventional motor control circuit;

[0060] Figure 8 is a voltage curve diagram of a motor control circuit according to an embodiment of the present invention.

[0061] Description of Figure Numbers:

[0062] 10-three-phase full-wave module; 20-power-off protection module; 30-rectifier soft-start module; 31-energy storage unit; BG1-rectifier bridge; VCC-preset reference voltage; J1-relay; L1-first inductor; CL1-first filter capacitor; CL2-second filter capacitor; R12-twelfth resistor; R13-thirteenth resistor; D1-first diode; Q1-first switch tube; R1-first resistor; ZD1-first voltage regulator diode; ZD2-second voltage regulator diode; C1-first capacitor; R2-second resistor; R14-fourteenth resistor; C5-fifth capacitor; K 1- clamping diode; R15- fifteenth resistor; R3- third resistor; R4- fourth resistor; Q2- second switch tube; C6- sixth capacitor; C7- seventh capacitor; A1- comparator; R5- fifth resistor; D2- second diode; D3- third diode; D4- fourth diode; R6- sixth resistor; R7- seventh resistor; R8- eighth resistor; C2- second capacitor; C3- third capacitor; C4- fourth capacitor; L2- second inductor; L3- third inductor; R9- ninth resistor; R10- tenth resistor; R11- eleventh resistor; Q3- third switch tube. DETAILED DESCRIPTION

[0063] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0065] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0067] With the development of motors, DC motors are widely used. Since most of the DC power supply of DC motors comes from the mains, it is basically obtained through mains rectification and capacitor filtering. The mains may cause power outages or power failures due to load overcurrent, line maintenance, environmental factors, etc. Some key equipment used in military, aviation, hospitals, banks, etc. are not allowed to be powered off. If a power outage or power failure occurs, it will cause immeasurable losses. Therefore, a backup power supply is used, and when a power outage or power failure occurs, it is switched to the backup power supply for operation.

[0068] refer to Figure 1 When the DC motor is running under load and the grid is powered off or out of power, and the motor switches to the backup power supply, the motor's energy storage unit will be discharged to a low potential, and then the electrolytic capacitor will be charged again, which will generate a large current. Therefore, the line will overcurrent and the switch will trip and the power will be cut off. Figure 7 ,like Figure 7 As shown in (A), the switching time is long and the capacitor discharges to 0V. Figure 7 As shown in (B), under normal circumstances, the voltage is discharged to 70V.

[0069] In this regard, a motor control circuit is provided in this embodiment, such as Figure 2 As shown, the motor control circuit is connected to the power conversion module, and the motor control circuit includes:

[0070] Specifically, the power conversion module may include a power grid, a backup power supply, a converter, a power switching relay conversion circuit, etc. When the power grid loses power, the power grid power supply is switched to the backup power supply through the converter and the power switching relay conversion circuit.

[0071] A three-phase full-wave module 10, the input end of which is connected to the power conversion module, for collecting the three-phase voltage signal transmitted by the power conversion module, rectifying the three-phase voltage signal to obtain a three-phase full-wave signal, and outputting the three-phase full-wave signal;

[0072] Specifically, the three-phase full-wave module 10 rectifies three voltage signals to obtain one three-phase full-wave signal. Optionally, the three-phase full-wave module 10 can be a rectifier.

[0073] A power-off protection module 20, which is connected to the output end of the three-phase full-wave module 10, and is used to receive a three-phase full-wave signal, and output a charging signal when it is detected that the three-phase full-wave signal is less than a preset switching value;

[0074] Specifically, the power-off protection module 20 is used to detect whether the three-phase full-wave signal is less than a preset switching value, so as to detect whether the power supply from the grid is switched to the backup power supply. If it is detected that the three-phase full-wave signal is less than the preset switching value, it is confirmed that the power supply from the grid is switched to the backup power supply, and a charging signal is output. Optionally, the power-off protection module 20 can be a switching device, which is used to output a switching signal when the received three-phase full-wave signal is less than the preset switching value.

[0075] The rectifier soft start module 30 has a built-in energy storage unit 31 . The rectifier soft start module 30 is connected to the power conversion module and the power-off protection module 20 respectively, and is used to charge the energy storage unit 31 after receiving a charging signal.

[0076] Specifically, the rectifier soft start module 30 has a built-in energy storage unit 31, and the two ends of the energy storage unit 31 are the output BUS voltage. The energy storage unit 31 is specifically an electrolytic capacitor or a filter capacitor. After receiving the charging signal, the rectifier soft start module 30 disconnects the line originally connected to the energy storage unit 31 and charges the energy storage unit 31 through another line. Optionally, the rectifier soft start module 30 includes a power supply device and a switching device.

[0077] In the motor control circuit provided by the present invention, a three-phase full-wave module receives a three-phase voltage signal and outputs a three-phase voltage signal, a power-off protection module outputs a charging signal when detecting that the three-phase voltage signal is less than a preset switching value, and a rectifier soft-start module charges an energy storage unit built into the rectifier soft-start module after receiving the charging signal, thereby charging the backup power supply when the power grid power supply is switched to the backup power supply, thereby preventing the energy storage unit from discharging to a low potential and generating a large current when charging again.

[0078] In some optional embodiments, such as Figure 3 As shown, the rectifier soft start module 30 includes:

[0079] A rectifier bridge BG1, wherein an input end of the rectifier bridge BG1 is connected to a power conversion module;

[0080] Specifically, refer to Figure 3 The rectifier bridge BG1 is composed of six diodes. Of course, the rectifier bridge BG1 is composed of any number of diodes or any devices. The rectifier bridge BG1 is used to rectify the three-phase voltage signal and transmit it to the energy storage unit 31.

[0081] refer to Figure 3The energy storage unit 31 includes a first filter capacitor CL1, a second filter capacitor CL2, a twelfth resistor R12 and a thirteenth resistor R13, wherein the first filter capacitor CL1 and the second filter capacitor CL2 are main filter capacitors, and the twelfth resistor R12 and the thirteenth resistor R13 are main filter capacitor equalizing resistors, which play a role in balancing the capacitor voltage.

[0082] Relay J1, a first control end of the relay J1 is connected to the output end of the rectifier bridge BG1, a second control end of the relay J1 is connected to the energy storage unit 31, a first power end of the relay J1 is connected to a preset reference voltage VCC, a second power end of the relay J1 is connected to the power-off protection module 20, and after receiving the charging signal, the second power end of the relay J1 disconnects the rectifier bridge BG1 and the energy storage unit 31;

[0083] Specifically, refer to Figure 3 , the first control end of the relay J1 is the 4th pin, the second control end of the relay J1 is the 3rd pin, the first power supply end of the relay J1 is the 1st pin, the second power supply end of the relay J1 is the 8th pin, and the 5th pin and the 6th pin of the relay J1 are spare pins. The first power supply end and the second power supply end of the relay J1 can be specifically the first conduction end and the second conduction end. When the first conduction end and the second conduction end are connected, the first control end and the second control end are connected. When the relay J1 receives the charging signal, the connection between the 4th pin and the 3rd pin is disconnected, thereby disconnecting the connection between the three-phase voltage signal and the filter capacitor.

[0084] The first inductor L1, the first end of the first inductor L1 is connected to the first control end of the relay J1, the second end of the first inductor L1 is connected to the second control end of the relay J1, when the relay J1 disconnects the rectifier bridge BG1 and the energy storage unit 31, the energy storage unit is charged through the first inductor L1.

[0085] Specifically, when the relay J1 is disconnected, the three-phase voltage signal of the first inductor L1 flows to the first inductor L1 through the rectifier bridge BG1, and the first inductor L1 charges the first filter capacitor CL1 and the second filter capacitor CL2, thereby preventing the first filter capacitor CL1 and the second filter capacitor CL2 from generating a large current when charging again after power failure. Optionally, the charging device can be a device other than the first inductor L1 for charging.

[0086] In some optional embodiments, such as Figure 3 As shown, the rectifier soft start module includes:

[0087] The first diode D1 has a first end connected to a first power supply end of the relay J1 , and a second end connected to a second power supply end of the relay J1 .

[0088] Specifically, the first diode D1 offsets the reverse voltage energy of the coil of the relay J1.

[0089] In some optional embodiments, such as Figure 4 As shown, the power-off protection module 20 includes:

[0090] A first zener diode ZD1, a first end of the first zener diode ZD1 is connected to the three-phase full-wave module 10;

[0091] A first resistor R1, wherein a first end of the first resistor R1 is connected to a second end of a first voltage stabilizing diode ZD1;

[0092] Specifically, the first voltage stabilizing diode ZD1 and the first resistor R1 form a trigger circuit. The first resistor R1 provides working conditions for driving the first switch tube Q1.

[0093] A first switch tube Q1, wherein a control end of the first switch tube Q1 is connected to a second end of the first resistor R1, a first end of the first switch tube Q1 is connected to a rectifier soft-start module 30, and a second end of the first switch tube Q1 is grounded;

[0094] When the first switch tube Q1 detects that the three-phase full-wave signal is less than a preset switching value, it is turned off and outputs a charging signal.

[0095] Specifically, when the grid voltage is normally powered, the first switch tube Q1 is in the on state. When the grid voltage is instantly powered off or switched to another power supply, the first switch tube Q1 is turned off, and the second power supply terminal that transmits negative power to the relay J1 is disconnected to output to the relay J1, so that the first control terminal and the second control terminal of the relay J1 are disconnected.

[0096] In some optional embodiments, such as Figure 4 As shown, the power-off protection module 20 is connected to the fault protection module. When the fault protection module detects that the power-off protection module outputs a charging signal, the fault protection module transmits a shutdown signal to the motor drive module through the shutdown control module and the main control module, so that the motor drive module stops driving the motor.

[0097] Specifically, when the grid voltage is normal, the voltage of the second power supply terminal of the relay J1 is detected to be 0. When the fault protection module detects that the second power supply terminal of the relay J1 is a high voltage, it is confirmed that the power-off protection module outputs a charging signal. At this time, the shutdown signal is transmitted to the motor drive module through the shutdown control module and the main control module to stop driving the motor. Therefore, when the relay J1 is disengaged, the motor is shut down immediately to protect the motor. Optionally, the fault protection module is specifically an overcurrent protection or overvoltage protection module.

[0098] In some optional embodiments, such as Figure 5 As shown, the circuit includes:

[0099] A voltage detection module 40, which is connected to the energy storage unit 31 and the fault protection module respectively, and is used to output a start signal to the fault protection module when it is detected that the voltage of the energy storage unit 31 is greater than a preset voltage value, wherein the start signal is transmitted to the main control module via the shutdown control module;

[0100] Specifically, refer to Figure 5 , the voltage of the energy storage unit 31 specifically refers to the BUS voltage (DC bus voltage), and the voltage detection module 40 is mainly used to output a start signal to the fault protection module when it is detected that the first inductor L1 fully charges the energy storage unit 31, so that the relay J1 is connected to the energy storage unit 31, and the first inductor L1 is short-circuited. It should be noted that the preset voltage value is the same as the voltage when the energy storage unit 31 is fully charged, or is adjusted according to the voltage when the energy storage unit 31 is fully charged. Optionally, the voltage detection module 40 can be specifically a comparison module.

[0101] The power-off protection module 20 further includes:

[0102] A second switch tube Q2, wherein the control end of the second switch tube Q2 is connected to the main control module, the first end of the second switch tube Q2 is connected to the control end of the first switch tube Q1, the second end of the second switch tube Q2 is grounded, and the second switch tube Q2 is closed after receiving the start signal to turn on the first switch tube Q1, so that the first switch tube Q1 stops outputting the charging signal;

[0103] The main control module sends a start signal to the control end of the second switch tube Q2. The second switch tube Q2 is turned off after receiving the start signal. At this time, the first switch tube Q1 is turned on and stops outputting the charging signal, connecting the relay J1 to the energy storage unit 31.

[0104] A second voltage stabilizing diode ZD2, wherein a first end of the second voltage stabilizing diode ZD2 is connected to the control end of the first switch tube Q1, and a second end of the second voltage stabilizing diode ZD2 is grounded;

[0105] Specifically, the second voltage stabilizing diode ZD2 is used to enable the circuit to operate at a stable voltage.

[0106] A first capacitor C1, wherein a first end of the first capacitor C1 is connected to a control end of the first switch tube Q1, and a second end of the first capacitor C1 is grounded;

[0107] Specifically, the first capacitor C1 plays a role in stabilizing the voltage between the first end and the second end of the second switch tube Q2.

[0108] The second resistor R2 has a first end connected to the control end of the first switch tube Q1 and a second end grounded.

[0109] Specifically, the second resistor R2 plays the role of a voltage dividing resistor and a discharge resistor.

[0110] In some optional embodiments, such as Figure 5 As shown, the voltage detection module 40 includes:

[0111] Comparator A1, a first input end of the comparator A1 is connected to the energy storage unit 31, an output end of the comparator A1 is connected to the fault protection module, and when the comparator A1 detects that the voltage of the energy storage unit 31 is greater than a preset voltage value, the comparator A1 outputs a start signal to the fault protection module;

[0112] Specifically, the comparator A1 is used to compare the voltage of the energy storage unit 31 with a preset voltage value, and when it is detected that the voltage of the energy storage unit 31 is greater than the preset voltage value, it outputs a start signal to the fault protection module. At this time, the start signal is transmitted to the main control module through the shutdown control module.

[0113] A third resistor R3, a first end of the third resistor R3 is connected to a preset reference voltage VCC, and a second end of the third resistor R3 is connected to a second input end of the comparator A1;

[0114] a fourth resistor R4, wherein a first end of the fourth resistor R4 is connected to a second end of the third resistor R3, and a second end of the fourth resistor R4 is grounded;

[0115] Specifically, after the third resistor R3 and the fourth resistor R4 are adjusted according to the preset reference voltage VCC, a preset voltage value is provided to the comparator A1.

[0116] a fifth resistor R5, wherein a first end of the fifth resistor R5 is connected to a preset reference voltage VCC, and a second end of the fifth resistor R5 is connected to an output end of the comparator A1;

[0117] Specifically, the fifth resistor R5 functions as a pull-up resistor.

[0118] A clamping diode K1 , a first end of the clamping diode K1 is connected to the first input end of the comparator A1 , a second end of the clamping diode K1 is connected to a preset reference voltage VCC, and a third end of the clamping diode K1 is grounded.

[0119] Specifically, the clamping diode K1 prevents surge voltage to prevent damage to the comparator A1.

[0120] In addition, the voltage detection module 40 may further include a fifth capacitor C5, a sixth capacitor C6 and a seventh capacitor C7. The fifth capacitor C5 filters the voltage at the first input terminal of the comparator A1, the seventh capacitor C7 filters the voltage at the second input terminal of the comparator A1, and the sixth capacitor C6 filters the voltage of the preset reference voltage VCC. The fourteenth resistor R14 and the fifteenth resistor R15 form a voltage divider resistor.

[0121] In some optional embodiments, such as Figure 6 As shown, the three-phase full-wave module 10 includes:

[0122] A second diode D2, wherein a first end of the second diode D2 is connected to the A-phase power supply end of the power conversion module, and a second end of the second diode D2 is connected to the power-off protection module 20;

[0123] A third diode D3, wherein a first end of the third diode D3 is connected to the B-phase power supply end of the power conversion module, and a second end of the third diode D3 is connected to the power-off protection module 20;

[0124] A fourth diode D4 , wherein a first end of the fourth diode D4 is connected to the C-phase power supply end of the power conversion module, and a second end of the fourth diode D4 is connected to the power-off protection module 20 .

[0125] Specifically, the second diode D2 filters the voltage at the A-phase power supply end, the third diode D3 filters the voltage at the B-phase power supply end, and the fourth diode D4 filters the voltage at the C-phase power supply end, and finally transmits the three-phase full-wave signal to the power-off protection module 20.

[0126] In some optional embodiments, such as Figure 6 As shown, the circuit includes:

[0127] An input filter module 50, wherein the first end of the input filter module 50 is connected to the power conversion module, and the second end of the input filter module 50 is respectively connected to the rectifier soft start module 30 and the three-phase full-wave module 10. The input filter module 50 is used to filter the three-phase voltage signal transmitted by the power conversion module, and transmit the filtered three-phase voltage signal to the rectifier soft start module 30 and the three-phase full-wave module 10 respectively.

[0128] Specifically, the input filter module 50 filters the three-phase voltage signal and transmits the filtered signal to the rectifier soft start module 30 and the three-phase full-wave module 10 respectively.

[0129] In some optional embodiments, such as Figure 6 As shown, the input filtering module 50 includes:

[0130] An A-phase filter unit consisting of a second capacitor C2, a sixth resistor R6 and a second inductor L2, wherein the second capacitor C2 is connected in parallel with the sixth resistor R6;

[0131] A B-phase filter unit consisting of a third capacitor C3, a seventh resistor R7 and a third inductor L3, wherein the third capacitor C3 is connected in parallel with the seventh resistor R7;

[0132] A C-phase filter unit is composed of a fourth capacitor C4, an eighth resistor R8 and a fourth inductor L4, wherein the fourth capacitor C4 is connected in parallel with the eighth resistor R8.

[0133] Specifically, the second capacitor C2, the sixth resistor R6 and the second inductor L2 filter the voltage of the A-phase power supply terminal, the third capacitor C3, the seventh resistor R7 and the third inductor L3 filter the voltage of the B-phase power supply terminal, and the fourth capacitor C4, the eighth resistor R8 and the fourth inductor L4 filter the voltage of the C-phase power supply terminal. Of course, the input filter module 50 can be composed of other devices to form a filter circuit.

[0134] In some optional embodiments, such as Figure 6 As shown, the circuit includes:

[0135] The discharge module 60 is connected to the three-phase full-wave module 10 and the power-off protection module 20 respectively, and releases the residual voltage of the second capacitor C2, the third capacitor C3 and the fourth capacitor C4 when detecting that the power-off protection module 20 sends a charging signal.

[0136] Specifically, when the power grid loses power instantly or switches to the backup power supply, the second capacitor C2, the third capacitor C3 and the fourth capacitor C4 have residual voltage, which causes the power failure protection module 20 to fail to work stably. Therefore, when it is detected that the power failure protection module 20 sends a charging signal, the discharge module 60 is turned on to release the residual voltage of the second capacitor C2, the third capacitor C3 and the fourth capacitor C4. Optionally, the discharge module 60 can be a switch device.

[0137] In some optional embodiments, such as Figure 6 As shown, the discharge module 60 includes:

[0138] A ninth resistor R9, a first end of the ninth resistor R9 is connected to the rectifier soft start module 30;

[0139] Specifically, the ninth resistor R9 functions as a driving resistor.

[0140] A third switch tube Q3, where a control end of the third switch tube Q3 is connected to a second end of a ninth resistor R9, and a first end of the third switch tube Q3 is grounded;

[0141] Specifically, when the power-off protection module 20 sends a charging signal, the second power supply terminal of the relay J1 is a high voltage, and the third switch tube Q3 is driven to turn on, and the residual voltage of the second capacitor C2, the third capacitor C3 and the fourth capacitor C4 is quickly released to the ground, thereby making the power-off protection module 20 work stably.

[0142] a tenth resistor R10, wherein a first end of the tenth resistor R10 is connected to the control end of the third switch tube Q3, and a second end of the tenth resistor R10 is grounded;

[0143] Specifically, the tenth resistor R10 functions as a discharge resistor.

[0144] An eleventh resistor R11 , a first end of the eleventh resistor R11 is connected to the three-phase full-wave module 10 , and a second end of the eleventh resistor R11 is connected to the second end of the third switch tube Q3 .

[0145] Specifically, the eleventh resistor R11 plays a role in voltage regulation.

[0146] The motor control circuit provided by the present invention refers to Figure 8 When the grid loses power instantly or switches to the backup power supply, the energy storage unit 31 is charged through the first inductor L1, and the voltage drop is only about 30Vdc, so that the normal operation of the motor is not affected.

[0147] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A motor control circuit, characterized in that: The motor control circuit is connected to the power conversion module, and the motor control circuit includes: A three-phase full-wave module, the input end of which is connected to the power conversion module, for collecting the three-phase voltage signal transmitted by the power conversion module, rectifying the three-phase voltage signal to obtain a three-phase full-wave signal, and outputting the three-phase full-wave signal; A power-off protection module, connected to the output end of the three-phase full-wave module, for receiving the three-phase full-wave signal, and outputting a charging signal when detecting that the three-phase full-wave signal is less than a preset switching value; A rectifier soft start module, wherein the rectifier soft start module has a built-in energy storage unit, and the rectifier soft start module is respectively connected to the power conversion module and the power-off protection module, and is used to charge the energy storage unit after receiving the charging signal.

2. The circuit according to claim 1, characterized in that The rectifier soft start module comprises: A rectifier bridge, wherein an input end of the rectifier bridge is connected to a power conversion module; A relay, wherein a first control end of the relay is connected to the output end of the rectifier bridge, a second control end of the relay is connected to the energy storage unit, a first power supply end of the relay is connected to a preset reference voltage, a second power supply end of the relay is connected to the power-off protection module, and after receiving the charging signal, the second power supply end of the relay disconnects the connection between the rectifier bridge and the energy storage unit; A first inductor, wherein a first end of the first inductor is connected to a first control end of the relay, and a second end of the first inductor is connected to a second control end of the relay, and when the relay disconnects the rectifier bridge and the energy storage unit, the energy storage unit is charged through the first inductor.

3. The circuit according to claim 2, characterized in that The rectifier soft start module comprises: A first diode, wherein a first end of the first diode is connected to a first power supply end of the relay, and a second end of the first diode is connected to a second power supply end of the relay.

4. The circuit according to claim 1, characterized in that The power-off protection module comprises: A first zener diode, wherein a first end of the first zener diode is connected to the three-phase full-wave module; a first resistor, wherein a first end of the first resistor is connected to a second end of the first voltage stabilizing diode; A first switch tube, wherein a control end of the first switch tube is connected to a second end of the first resistor, a first end of the first switch tube is connected to the rectifier soft-start module, and a second end of the first switch tube is grounded; Wherein, the first switch tube is turned off when it is detected that the three-phase full-wave signal is less than a preset switching value, and a charging signal is output.

5. The circuit according to claim 4, characterized in that The power-off protection module is connected to the fault protection module. When the fault protection module detects that the power-off protection module outputs a charging signal, the fault protection module transmits a shutdown signal to the motor drive module through the shutdown control module and the main control module, so that the motor drive module stops driving the motor.

6. The circuit according to claim 5, characterized in that The circuit comprises: A voltage detection module, the voltage detection module is connected to the energy storage unit and the fault protection module respectively, and is used to output a start signal to the fault protection module when it is detected that the voltage of the energy storage unit is greater than a preset voltage value, wherein the start signal is transmitted to the main control module through the shutdown control module; The power-off protection module also includes: a second switch tube, wherein the control end of the second switch tube is connected to the main control module, the first end of the second switch tube is connected to the control end of the first switch tube, the second end of the second switch tube is grounded, and the second switch tube is closed after receiving the start signal to turn on the first switch tube, so that the first switch tube stops outputting the charging signal; A second voltage stabilizing diode, wherein a first end of the second voltage stabilizing diode is connected to the control end of the first switch tube, and a second end of the second voltage stabilizing diode is grounded; A first capacitor, wherein a first end of the first capacitor is connected to the control end of the first switch tube, and a second end of the first capacitor is grounded; A second resistor, wherein a first end of the second resistor is connected to the control end of the first switch tube, and a second end of the second resistor is grounded.

7. The circuit according to claim 6, characterized in that The voltage detection module comprises: A comparator, wherein a first input end of the comparator is connected to the energy storage unit, an output end of the comparator is connected to the fault protection module, and when the comparator detects that the voltage of the energy storage unit is greater than a preset voltage value, the comparator outputs a start signal to the fault protection module; a third resistor, wherein a first end of the third resistor is connected to a preset reference voltage, and a second end of the third resistor is connected to a second input end of the comparator; a fourth resistor, wherein a first end of the fourth resistor is connected to a second end of the third resistor, and a second end of the fourth resistor is grounded; a fifth resistor, wherein a first end of the fifth resistor is connected to the preset reference voltage, and a second end of the fifth resistor is connected to the output end of the comparator; A clamping diode, wherein a first end of the clamping diode is connected to the first input end of the comparator, a second end of the clamping diode is connected to a preset reference voltage, and a third end of the clamping diode is grounded.

8. The circuit according to claim 1, characterized in that The three-phase full-wave module comprises: A second diode, wherein a first end of the second diode is connected to the A-phase power supply end of the power conversion module, and a second end of the second diode is connected to the power-off protection module; A third diode, a first end of the third diode is connected to the B-phase power supply terminal of the power conversion module, and a second end of the third diode is connected to the power-off protection module; A fourth diode, wherein a first end of the fourth diode is connected to the C-phase power supply end of the power conversion module, and a second end of the fourth diode is connected to the power-off protection module.

9. The circuit according to claim 1, characterized in that The circuit comprises: An input filter module, wherein the first end of the input filter module is connected to the power conversion module, and the second end of the input filter module is respectively connected to the rectifier soft start module and the three-phase full-wave module, and the input filter module is used to filter the three-phase voltage signal transmitted by the power conversion module, and transmit the filtered three-phase voltage signal to the rectifier soft start module and the three-phase full-wave module respectively.

10. The circuit according to claim 9, characterized in that The input filtering module comprises: An A-phase filter unit consisting of a second capacitor, a sixth resistor and a second inductor, wherein the second capacitor is connected in parallel with the sixth resistor; A B-phase filter unit consisting of a third capacitor, a seventh resistor and a third inductor, wherein the third capacitor is connected in parallel with the seventh resistor; A C-phase filter unit consisting of a fourth capacitor, an eighth resistor and a fourth inductor, wherein the fourth capacitor is connected in parallel with the eighth resistor.

11. The circuit according to claim 10, characterized in that The circuit comprises: A discharge module, wherein the discharge module is connected to the three-phase full-wave module and the power-off protection module respectively, and releases the residual voltage of the second capacitor, the third capacitor and the fourth capacitor when detecting that the power-off protection module sends a charging signal.

12. The circuit according to claim 11, characterized in that The discharge module comprises: a ninth resistor, wherein a first end of the ninth resistor is connected to the rectifier soft start module; a third switch tube, wherein a control end of the third switch tube is connected to the second end of the ninth resistor, and a first end of the third switch tube is grounded; a tenth resistor, wherein a first end of the tenth resistor is connected to the control end of the third switch tube, and a second end of the tenth resistor is grounded; An eleventh resistor, a first end of the eleventh resistor is connected to the three-phase full-wave module, and a second end of the eleventh resistor is connected to the second end of the third switch tube.

Images