CN205231713U - Novel low -tension motor protection and electric -dazzling prevention device - Google Patents

Abstract

The utility model discloses a new type of low-voltage motor protection and anti-sway device, which comprises an anti-sway circuit, a management circuit, a protection and restart circuit and a display circuit. The voltage circuit is connected, the control voltage circuit is connected with the motor, and the management circuit includes a central processing unit. The utility model anti-sway electric circuit can cut into the DC power supply when the power supply system is swaying, so that the contactor can be kept closed to prevent the motor from stopping due to the instantaneous swaying electricity; the management circuit can collect the working state information of the motor, and according to the working state The information controls the protection and restart circuit to work. The protection and restart circuit can control the disconnection and connection of the contactor, automatically disconnect the motor when the control voltage is low or loses voltage, and automatically restart the motor when the control voltage returns to normal.

Description

A new type of protection and anti-shake device for low-voltage motor

technical field

The utility model relates to a novel low-voltage motor protection and anti-sway electric device.

Background technique

During the use of the motor, due to the instability of the power supply system, there will be a shock phenomenon, which will cause the contactor in the control voltage circuit to be released suddenly during operation, and when the control voltage output by the power supply system returns to normal, all the motors will suddenly restart together , The voltage at the moment of restart is relatively large, which is easy to burn out the motor, and seriously affects the safety and stability, bringing economic losses and potential safety hazards to the enterprise. Therefore, it is necessary to provide a new motor protection circuit to solve the above problems.

Utility model content

The purpose of the utility model is to provide a new low-voltage motor protection and anti-sway device with anti-sway function and automatic batch restart motor function.

In order to achieve the above object, the technical scheme adopted in the utility model is as follows:

A new type of low-voltage motor protection and anti-sway device, including an anti-sway circuit, a management circuit, a protection and restart circuit, and a display circuit. The anti-sway circuit, protection and restart circuit, and display circuit are respectively connected to the The management circuit is connected, the output end of the anti-sway point circuit is connected to a contactor, the contactor is connected to a control voltage circuit, the control voltage circuit is connected to a motor, and the management circuit includes a central processing unit.

Preferably, the anti-shake circuit includes a first switching protection circuit, a switching circuit, a first energy storage circuit, a boost circuit and a half-bridge chopper circuit, the first energy storage circuit, the boost circuit and the The half-bridge chopper circuit is connected sequentially, the first power input terminal of the switching circuit is connected to the first power supply, and the second power input terminal of the switching circuit is connected to the output terminal of the half-bridge chopper circuit. A switching relay; the power output end of the switching circuit is connected to the input end of the first switching protection circuit, and the output end of the first switching protection circuit is connected to the contactor.

Preferably, the anti-shake circuit further includes a second switching protection circuit, the second switching protection circuit includes a current transformer, a comparator and a latch, and the input terminal of the current transformer is connected to the first power supply, the first output terminal of the current transformer is connected to the first input terminal of the comparator, the second output terminal of the current transformer is connected to the central processing unit, and the second input terminal of the comparator terminal input fixed value voltage, the output terminal of the comparator is connected with the first input terminal of the latch, the second input terminal of the latch is connected with the central processing unit, the latch of the The second input terminal is a reset control input terminal, the output terminal of the latch is connected to the switching circuit, and the output terminal of the latch is further connected to the central processing unit.

Preferably, the first energy storage circuit includes a first AC/DC conversion circuit, a first diode and a first supercapacitor group, the input terminal of the first AC/DC conversion circuit is connected to a second power supply, and the first An output terminal of an AC/DC conversion circuit is connected to the anode of the first diode, and the cathode of the first diode is connected to the first supercapacitor group, and the first supercapacitor group is further connected to the central processing unit; The boost circuit includes a first boost circuit, a second boost circuit, a high-voltage capacitor, a second diode and a third diode, and the input terminal of the first boost circuit is connected to the first supercapacitor group connection, the output end of the first boosting circuit is connected to the input end of the second boosting circuit, and the output end of the first boosting circuit is further connected to the anode of the second diode, so The cathode of the second diode is connected to the half-bridge chopper circuit, the high-voltage capacitor is connected between the output terminal of the second boost circuit and the ground wire, and the output terminal of the second boost circuit is connected to the ground wire. The anode of the third diode is connected, and the cathode of the third diode is connected with the cathode of the second diode.

Preferably, the management circuit further includes a voltage transformer, a second energy storage circuit and a power conversion circuit, the input end of the voltage transformer is connected to the control voltage circuit, and the output end of the voltage transformer is connected to the The central processing unit is connected, the second energy storage circuit includes a second AC/DC conversion circuit, a fourth diode and a second supercapacitor group, and the input end of the second AC/DC conversion circuit is connected to the first Two power supplies, the output end of the second AC/DC conversion circuit is connected to the anode of the fourth diode, and the cathode of the fourth diode is connected to the second supercapacitor group, and the second supercapacitor group is further connected to the central The processing unit is connected, the power conversion circuit includes a DC/DC conversion circuit and a linear power supply, the input end of the DC/DC conversion circuit is connected to the second supercapacitor bank, and the output end of the DC/DC conversion circuit is connected to the the linear power connection.

Preferably, the protection and restart circuit includes a current acquisition circuit, a relay control circuit and a binary input detection circuit, the relay control circuit includes first to fourth relays, and the binary input detection circuit includes a first optocoupler circuit and a second optocoupler circuit, each optocoupler circuit includes a photocoupler and a second resistor, the first end of the second resistor is connected to the binary input to be detected, and the second end of the second resistor is connected to the second resistor The input end of the optocoupler is connected, and the output end of the optocoupler is connected with the central processing unit.

Compared with the prior art, the beneficial effect of the new low-voltage motor protection and anti-sway device of the utility model is that the anti-sway circuit can cut into the DC power supply when the power supply system swayes, so that the contactor remains closed, Prevent the motor from stopping due to instantaneous shaking; the management circuit can collect the working status information of the motor, and control the protection and restart circuit according to the working status information, and the protection and restart circuit can control the contactor to disconnect When the control voltage is low or lost, it will automatically disconnect the motor, and automatically restart the motor when the control voltage returns to normal.

Description of drawings

Fig. 1 is the schematic diagram of the low-voltage electric motor protection of the utility model and anti-sway electric device;

Fig. 2 is the schematic diagram of the second switching protection circuit described in the utility model;

Fig. 3 is the main loop program flow chart of the control method of the low-voltage motor protection and anti-shaking electric device of the utility model;

Fig. 4 is the program flowchart of protection logic described in the utility model;

Fig. 5 is a program flow chart of the pressure loss restart logic described in the present invention;

FIG. 6 is a program flow chart of the anti-shake logic of the present invention.

The marks in the figure are as follows: 1. Anti-sway circuit; 101. First energy storage circuit; 102. Second switching protection circuit; 2. Management circuit; 201. Second energy storage circuit; 3. Protection and restart circuit; D1, the first diode; D2, the second diode; D3, the third diode; D4, the fourth diode; relay1, the first relay; relay2, the second relay; relay3, the third relay; relay4, fourth relay; relay5, switching relay; R1, first resistor; R2, second resistor; C1, first capacitor; E, high voltage capacitor; RZ, adjustable resistor; FZ, fuse; CT, current transformer ; PT, voltage transformer; LDO, linear power supply.

detailed description

The utility model is further described below in conjunction with specific embodiments.

Please refer to Figures 1 to 6, the utility model provides a new type of low-voltage motor protection and anti-sway device, including anti-sway circuit 1, management circuit 2, protection and restart circuit 3 and display circuit, the The anti-sway circuit 1, the protection and restart circuit 3 and the display circuit are respectively connected to the management circuit 2, the output end of the anti-sway point circuit is connected to a contactor, and the contactor is connected to a control voltage circuit. The voltage circuit is connected with the motor, and the management circuit 2 includes a central processing unit, which includes a microprocessor and peripheral circuits.

Wherein, the anti-shake electric circuit 1 includes a first switching protection circuit, a switching circuit, a first energy storage circuit 101, a boost circuit and a half-bridge chopper circuit, the first energy storage circuit 101, the boost circuit It is sequentially connected with the half-bridge chopper circuit, the first power input terminal of the switching circuit is connected to the first power supply, and the second power input terminal of the switching circuit is connected to the output terminal of the half-bridge chopper circuit. A switching relay relay5 is connected; the power output end of the switching circuit is connected to the input end of the first switching protection circuit, and the output end of the first switching protection circuit is connected to the contactor.

In this embodiment, the first switching protection circuit includes an adjustable resistor RZ, a first resistor R1, a first capacitor C1 and a fuse FZ, and the adjustable resistor RZ is connected in parallel between the output end of the switching circuit and Between the contactors, the first resistor R1 is connected in series with the first capacitor C1 and then connected in parallel with the adjustable resistor RZ, and the fuse FZ is connected in series between the output end of the switching circuit and between the contactors. The first switching protection circuit can prevent damage to the circuit caused by an overvoltage generated during the process of switching the contactor to input electric energy.

The anti-shake circuit 1 also includes a second switching protection circuit 102, the second switching protection circuit 102 includes a current transformer CT, a comparator and a latch, and the input terminal of the current transformer CT is connected to the The first power supply, the first output terminal of the current transformer CT is connected to the first input terminal of the comparator, the second output terminal of the current transformer CT is connected to the central processing unit, and the comparator The second input terminal of the second input terminal (that is, pin a) inputs a preset fixed value voltage, and the fixed value voltage is denoted as Ua, and the output terminal of the comparator is connected with the first input terminal of the latch, so The second input end of the latch is connected to the central processing unit, the second input end of the latch is a reset control input end, the output end of the latch is connected to the switching circuit, and the The output terminal of the latch is further connected with the central processing unit.

The first energy storage circuit 101 includes a first AC/DC conversion circuit, a first diode D1 and a first supercapacitor group, the input terminal of the first AC/DC conversion circuit is connected to a second power supply, and the first The output end of the AC/DC conversion circuit is connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected to the first supercapacitor group, and the first supercapacitor group is further connected to the central processing unit ; The boost circuit includes a first boost circuit, a second boost circuit, a high voltage capacitor E, a second diode D2 and a third diode D3, the input terminal of the first boost circuit is connected to the The first supercapacitor bank is connected, the output end of the first boost circuit is connected to the input end of the second boost circuit, and the output end of the first boost circuit is further connected to the second diode D2 The anode of the second diode D2 is connected, the cathode of the second diode D2 is connected to the half-bridge chopper circuit, the high-voltage capacitor E is connected between the output terminal of the second boost circuit and the ground, and the second The output end of the boost circuit is connected to the anode of the third diode D3, and the cathode of the third diode D3 is connected to the cathode of the second diode D2.

As shown in Figure 1, CL and CN are the input terminals of the first power supply, XL and XN are the output terminals of the anti-shaking electric circuit 1, the first power supply is alternating current, when the first power supply is short-circuited, the current transformer CT The voltage at the first output terminal is greater than Ua, the comparator outputs a blocking signal, which is locked by the latch, and the blocking signal causes the switching circuit to cut off the first power supply, thereby protecting the circuit. PL and PN are the input ends of the second power supply, the second power supply is alternating current, the first AC/DC conversion circuit converts the second power supply into 15V direct current, and the 15V direct current charges the first supercapacitor bank, and the capacity of the first supercapacitor bank is 30 joules, the first boost circuit converts 15V DC into 24V or 96V DC, that is, the voltage Ub at point b in Figure 1 is 24V or 96V, and the second boost circuit converts 24V or 96V DC into 220V DC, as shown in Figure 1 The voltage Uc at point c in the middle is 220V. Both the first booster circuit and the second booster circuit use BOOST booster modules, which have a wide input voltage range and can make full use of the energy storage of the first supercapacitor group. The half-bridge chopper circuit can convert 220V DC into a controllable DC voltage output. When the first power supply is cut off by the switching circuit, the central processing unit controls the switching circuit to close the switch of the switching relay relay5 and connect to the half-bridge chopper. The controllable DC voltage output by the wave circuit keeps the contactor closed. When the power supply of the first power supply is normal, the central processing unit controls the switch of the switching relay relay5 to turn off, and at the same time outputs a reset signal to reset the latch, the latch signal is released, and the first power supply continues to supply power to the contactor.

The management circuit 2 also includes a voltage transformer PT, a second energy storage circuit 201 and a power conversion circuit, the input end of the voltage transformer PT is connected to the control voltage circuit, and the output end of the voltage transformer PT is connected to the control voltage circuit. The central processing unit is connected, the second energy storage circuit 201 includes a second AC/DC conversion circuit, a fourth diode D4 and a second supercapacitor bank, and the input terminal of the second AC/DC conversion circuit is connected to The second power supply is input, the output end of the second AC/DC conversion circuit is connected to the anode of the fourth diode D4, and the cathode of the fourth diode D4 is connected to the second supercapacitor group, and the second supercapacitor group is further connected with the central processing unit, the power conversion circuit includes a DC/DC conversion circuit and a linear power supply LDO, the input end of the DC/DC conversion circuit is connected with the second supercapacitor bank, and the DC/DC conversion circuit The output end of the DC conversion circuit is connected with the linear power supply LDO.

As shown in Figure 1, the input terminal of the voltage transformer PT inputs the control voltage Uac of the motor, and the control voltage Uac is converted by the voltage transformer PT to form a collection voltage that the central processing unit can recognize. The control voltage Uac. The second AC/DC conversion circuit converts the second power supply into 15V DC, and the 15V DC charges the second supercapacitor bank. The capacity of the first supercapacitor bank is 15 Joules. The DC/DC conversion circuit converts 15V DC into 24V DC, linear The power supply LDO converts 24V DC into 5V DC, and 24V DC and 5V DC provide power for each component in the circuit. In a specific application, the management circuit 2 also includes a communication interface, and the central processing unit is connected with the host computer to exchange data according to the communication interface.

The protection and restart circuit 3 includes a current acquisition circuit, a relay control circuit and a binary input detection circuit, the relay control circuit includes first to fourth relay relay4, and the binary input detection circuit includes a first optocoupler circuit and a second optocoupler circuit, each optocoupler circuit includes a photocoupler and a second resistor R2, the first end of the second resistor R2 is connected to the binary input to be detected, and the second end of the second resistor R2 It is connected with the input end of the photoelectric coupler, and the output end of the photoelectric coupler is connected with the central processing unit.

Wherein, the current collection circuit collects the working current IA, IB and IC of the motor, and collects the leakage current IL at the same time. After processing, IA, IB, IC and IL are converted into collection currents that can be recognized by the central processing unit and sent to the central control unit. , the central processing unit calculates the working current of the motor according to the collected current. The first to fourth relays respectively include a coil and a switch, the switch of the first relay relay1 is connected in series in the circuit where the contactor is located, the switch of the second relay relay2 is connected in series in the circuit where the circuit breaker is located, and the switch of the third relay relay3 is connected in series The switch of the fourth relay relay4 is connected in series in the circuit where the motor starting circuit is located, and the switch of the fourth relay relay4 is connected in series in the circuit where the contactor state holding circuit is located. The binary input is connected to the binary input detection circuit through 24V DC and external dry contacts, and enters the photocoupler after being divided by the second resistor R2. The photocoupler converts the electrical signal into an optical signal and then becomes an electrical signal again Output to the central processing unit for the central processing unit to collect external binary input information.

The display circuit includes a liquid crystal display screen, operation buttons and indicator lights. The display circuit communicates with the management circuit 2, and the display circuit can be configured with protection setting values, system parameter setting values, some binary input values, analog data viewing, and other information display. The information that the user needs to set is set in the management circuit 2 through the keys and the prompts of the liquid crystal display.

In specific applications, in order to facilitate wiring management and communication between circuits, the anti-shake circuit 1, management circuit 2, protection and restart circuit 3 and display circuit can be respectively provided with interfaces.

The control method of the novel low-voltage motor protection and anti-sway electric device described in the utility model comprises the following steps:

a) system initialization;

b) display circuit display program;

c) Enter the protection logic;

d) Enter the pressure-loss restart logic;

e) Enter the anti-shake logic;

f) Enter the binary input reading logic;

g) Relay control circuit action;

h) Return to step b).

The protection logic described in step c) includes the following steps:

a1) Identify the protection and restart circuit 3, if the identification is successful, enter the next step, if the identification fails, the protection logic ends;

b1) Calculate the working current of the motor according to the collected current of the motor;

c1) Start the motor current protection program;

d1) Calculate the working voltage of the motor according to the collected voltage of the motor;

e1) Start the motor voltage protection program;

f1) Calculate the power of the motor;

g1) Start the motor underload protection program;

h1) The protection logic ends.

The pressure loss restart logic described in step d) includes the following steps:

a2) Identification protection and restart circuit 3, if the identification is successful, enter the next step, if the identification fails, the power interruption counter PC is cleared, and the restart logic ends when the voltage is lost;

b2) Calculate the working voltage of the motor;

c2) Judging whether the operating current value of the motor is greater than a preset critical value (denoted as Isq), if it is greater than and enters the next step, if it is less than, the power interruption counter PC is cleared, and the restart logic ends when the voltage is lost;

d2) judging whether the operating voltage of the motor decreases suddenly, if it enters step f2), if not enters the next step;

e2) Judging whether the working voltage of the motor decreases slowly, if it enters the next step, if otherwise, the power interruption counter PC is cleared, and the restart logic ends when the voltage is lost;

f2) Determine whether the contactor is tripped, if so, add 1 to the power interruption counter PC, and enter the next step, if otherwise, clear the power interruption counter PC to zero, and the restart logic ends when the voltage is lost;

g2) Detect whether the count value of the power interruption counter PC exceeds the preset protection times value (marked as X1), if it does not exceed and enter the next step, if it exceeds, the power interruption counter PC is cleared, and the restart logic ends when the voltage is lost;

h2) Detect whether the working voltage of the motor returns to normal, if it returns to normal, enter the next step, if not, reset the power interruption counter PC to zero, and the restart logic ends when the voltage is lost;

i2) Control the action of the relay control circuit, restart the motor, clear the power interruption counter PC, and end the restart logic after voltage loss.

The anti-shake electric logic described in step e) comprises the following steps:

a3) Identify the anti-sway circuit 1, if the identification is successful, enter the next step, if the identification fails, the anti-sway holding counter PC is cleared, and the anti-sway logic ends;

b3) Determine whether the working voltage of the motor is normal, if it is normal, go to the next step, if not, clear the anti-sway electric holding counter PC, and the anti-sway electric logic ends;

c3) Judging whether the working current of the motor is normal, if it is normal, enter the next step, if it is not normal, the anti-sway electric holding counter PC is cleared, and the anti-sway electric logic ends;

d3) Judging whether the energy storage of the first supercapacitor group is normal, if it is normal to calculate the DC voltage output by the booster circuit, enter the next step, if not normal, clear the anti-sway power holding counter PC, and the anti-sway power logic ends;

e3) judging whether the operating voltage of the motor decreases suddenly, if it enters step g3), if not enters the next step;

f3) Judging whether the working voltage of the motor decreases slowly, if it enters the next step, if not, clears the anti-sway power holding counter PC, and the anti-sway power logic ends;

g3) The switching circuit blocks the output of the first power supply, the half-bridge chopper circuit adjusts the magnitude of the DC voltage output by the booster circuit, the switch of the switching relay relay5 is closed, the DC voltage is cut in, and the anti-sway holding counter PC is increased by 1;

h3) Judging whether the count value of the anti-sway electric hold counter PC exceeds the preset restart count value (denoted as X2), if it does not exceed the anti-sway electric logic to end, if it exceeds, the switch of the switching relay relay5 is turned off, and the circuit is switched Cut into the first power supply, and the anti-shake logic ends.

To sum up, the anti-sway electric circuit 1 of the present utility model can cut into the DC power supply when the power supply system is swayed, so that the contactor can be kept closed to prevent the motor from stopping due to the instantaneous swaying electricity; the management circuit 2 can collect the work of the motor State information, and control the work of the protection and restart circuit 3 according to the working state information. The protection and restart circuit 3 can control the disconnection and connection of the contactor, automatically disconnect the motor when the control voltage is low or loses voltage, and automatically disconnect the motor when the control voltage is restored. Automatically restart the motor when it is normal, and when restarting the motor, it can control different motors to be started in batches to protect the circuit.

The above schematically describes the utility model and its implementation, which is not restrictive, and what is shown in the accompanying drawings is only one implementation of the utility model, and the actual structure is not limited thereto. Therefore, if a person of ordinary skill in the art is inspired by it, and without departing from the purpose of the invention of the utility model, without creatively designing a structural mode and an embodiment similar to the technical solution, it shall belong to the utility model. protected range.

Claims (6)

1. A new type of low-voltage motor protection and anti-swaying device, characterized in that it includes an anti-swaying circuit, a management circuit, a protection and restart circuit and a display circuit, and the anti-swaying circuit, protection and restarting circuit and The display circuit is respectively connected to the management circuit, the output end of the anti-shake point circuit is connected to a contactor, the contactor is connected to the control voltage circuit, the control voltage circuit is connected to the motor, and the management circuit includes a central processing unit . 2. The novel low-voltage motor protection and anti-sway device according to claim 1, wherein the anti-sway circuit includes a first switching protection circuit, a switching circuit, a first energy storage circuit, a boost circuit and A half-bridge chopper circuit, the first energy storage circuit, the boost circuit and the half-bridge chopper circuit are sequentially connected, the first electric energy input terminal of the switching circuit is connected to the first power supply, and the switching circuit A switching relay is connected between the second power input end of the second power input end of the half-bridge chopper circuit; the power output end of the switching circuit is connected to the input end of the first switching protection circuit, and the first switching The output terminal of the protection circuit is connected with the contactor. 3. The novel low-voltage motor protection and anti-sway device according to claim 2, wherein the anti-sway circuit also includes a second switching protection circuit, and the second switching protection circuit includes a current transformer, A comparator and a latch, the input terminal of the current transformer is connected to the first power supply, the first output terminal of the current transformer is connected to the first input terminal of the comparator, and the current transformer The second output end of the comparator is connected with the central processing unit, the second input end of the comparator inputs a fixed value voltage, the output end of the comparator is connected with the first input end of the latch, and the lock The second input end of the latch is connected with the central processing unit, the second input end of the latch is a reset control input end, the output end of the latch is connected with the switching circuit, and the latch The output terminal of the device is further connected with the central processing unit. 4. The new low-voltage motor protection and anti-shake device according to claim 2, wherein the first energy storage circuit includes a first AC/DC conversion circuit, a first diode and a first supercapacitor group, the input end of the first AC/DC conversion circuit is connected to the second power supply, the output end of the first AC/DC conversion circuit is connected to the anode of the first diode, and the cathode of the first diode is connected to the first The supercapacitor bank is connected, and the first supercapacitor bank is further connected with the central processing unit; the boost circuit includes a first boost circuit, a second boost circuit, a high voltage capacitor, a second diode and a third boost circuit. diode, the input end of the first boost circuit is connected to the first supercapacitor bank, the output end of the first boost circuit is connected to the input end of the second boost circuit, and the first boost circuit The output terminal of a boost circuit is further connected to the anode of the second diode, the cathode of the second diode is connected to the half-bridge chopper circuit, and the output terminal of the second boost circuit is connected to the The high-voltage capacitor is connected between the ground wires, the output terminal of the second boost circuit is connected to the anode of the third diode, and the cathode of the third diode is connected to the anode of the second diode. Cathode connection. 5. The novel low-voltage motor protection and anti-shaking device as claimed in claim 1, wherein the management circuit also includes a voltage transformer, a second energy storage circuit and a power conversion circuit, and the voltage transformer's The input end is connected to the control voltage circuit, the output end of the voltage transformer is connected to the central processing unit, and the second energy storage circuit includes a second AC/DC conversion circuit, a fourth diode and a second The supercapacitor bank, the input end of the second AC/DC conversion circuit is connected to the second power supply, the output end of the second AC/DC conversion circuit is connected to the anode of the fourth diode, and the anode of the fourth diode The cathode is connected to the second supercapacitor bank, the second supercapacitor bank is further connected to the central processing unit, the power conversion circuit includes a DC/DC conversion circuit and a linear power supply, and the input terminal of the DC/DC conversion circuit It is connected with the second supercapacitor bank, and the output terminal of the DC/DC conversion circuit is connected with the linear power supply. 6. The novel low-voltage motor protection and anti-shaking device as claimed in claim 1, wherein the protection and restart circuit includes a current acquisition circuit, a relay control circuit and a binary input detection circuit, and the relay control The circuit includes first to fourth relays, the binary input detection circuit includes a first optocoupler circuit and a second optocoupler circuit, each optocoupler circuit includes a photocoupler and a second resistor, and the second resistor of the second resistor One end is connected to the binary input to be detected, the second end of the second resistor is connected to the input end of the optocoupler, and the output end of the optocoupler is connected to the central processing unit.