High-voltage high-power motor control system based on frequency converter and solid-state soft start

Abstract

The utility model relates to a high-voltage high-power motor control system based on a frequency converter and solid-state soft start, which comprises a high-voltage high-power motor, a superior power circuit breaker QF, a circuit breaker 1QF, a circuit breaker 2QF, a circuit breaker QF11 and a circuit breaker QF12, and a soft starter and a frequency converter which are mutually standby, the leading-out terminal of the superior power circuit breaker QF is connected with the input terminal of the soft starter through a normally open contact of the circuit breaker 1QF, and the leading-out terminal of the superior power circuit breaker QF is connected with the output terminal of the frequency converter. The output end of the soft starter is connected to the power supply input end of the motor through a circuit breaker 2QF; the wire outlet end of the QF is connected to the input end of the frequency converter through a circuit breaker QF11, and the output end of the frequency converter is connected to the power input end of the motor through a circuit breaker QF12. According to the motor control system provided by the utility model, on the basis of ensuring economical efficiency, stable field operation is ensured to the greatest extent, timely investment of a motor or equipment is ensured, quick response control is realized, the automation degree of field control can be greatly improved, the field maintenance amount is reduced, and the motor control system is worthy of vigorous popularization.

Description

Technical Field

[0001] The utility model relates to a high-voltage and high-power motor control system, and more specifically, to a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter. Background Art

[0002] At present, for domestic high-power high-voltage motors, the main driving method used is a single high-voltage inverter or a single solid-state soft starter. The use of a single controller (inverter or soft starter) is limited in applicability to important load systems. It cannot cope with the non-stop switching of high-voltage motors when the inverter or soft starter fails. Moreover, when the soft starter or inverter that controls the operation of the high-voltage motor fails, it cannot be repaired without stopping the machine, and it cannot meet the needs of daily non-stop maintenance.

[0003] Since high-power and high-voltage motors use a high-voltage inverter or a high-voltage solid-state soft starter to control the operation of the motor, when controlling the operation of high-power and important motors, if the inverter or soft starter fails, the motor can only run at the industrial frequency. However, when the fault is converted to the industrial frequency, the impact on the power grid is too great, and when the motor stops, the industrial frequency starting conditions cannot be met on site, affecting the stable operation of the motor on site. Summary of the invention

[0004] In order to overcome the disadvantages of the above technical problems, the utility model provides a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter.

[0005] The utility model discloses a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter, comprising a high-voltage and high-power motor, an upper power circuit breaker QF, a circuit breaker 1QF, a circuit breaker 2QF, a circuit breaker QF11 and a circuit breaker QF12, wherein the incoming line terminal of the upper power circuit breaker QF is connected to the high-voltage AC busbar; the utility model is characterized in that the utility model also comprises a soft starter and a frequency converter which are standby for each other, the outgoing line terminal of the upper power circuit breaker QF is connected to the input end of the soft starter via the normally open point of the circuit breaker 1QF, and the output end of the soft starter is connected to the power input end of the high-voltage and high-power motor via the circuit breaker 2QF; the outgoing line terminal of the upper power circuit breaker QF is connected to the input end of the frequency converter via the circuit breaker QF11, and the output end of the frequency converter is connected to the power input end of the high-voltage and high-power motor via the circuit breaker QF12.

[0006] The utility model discloses a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter, comprising a circuit breaker 3QF, wherein the incoming line terminal of the circuit breaker 3QF is connected to the outgoing line terminal of the upper power circuit breaker QF, and the outgoing line terminal of the circuit breaker 3QF is connected to the power input terminal of the high-voltage and high-power motor.

[0007] The utility model discloses a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter, wherein the circuit breaker QF11 is connected in parallel with a power-on buffer circuit, and the power-on buffer circuit is composed of a buffer contactor KM2 and a buffer resistor; one end of the normally open point of the buffer contactor KM2 is connected to the incoming line end of the circuit breaker QF11, and the other end of the normally open point is connected to the outgoing line end of the circuit breaker QF11 via a buffer resistor.

[0008] The utility model discloses a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter. The frequency converter is composed of a phase-shifting transformer and an inverter power unit. The input end of the phase-shifting transformer forms the input end of the frequency converter, the output end of the phase-shifting transformer is connected to the input end of the inverter power unit, and the output end of the inverter power unit forms the output end of the frequency converter.

[0009] The utility model discloses a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter. An AC transformer TA1 is arranged on the input end of the frequency converter, and an AC transformer TA2, an AC transformer TA3 and a voltage detection board are arranged on the output end of the frequency converter.

[0010] The utility model discloses a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter, wherein the circuit breaker 1QF and the soft starter are arranged in a soft start cabinet, the circuit breaker 2QF and the circuit breaker 3QF are arranged in a soft start isolation cabinet, and the circuit breaker QF11, the circuit breaker QF12 and the frequency converter are arranged in a frequency converter cabinet.

[0011] The utility model discloses a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter, wherein the circuit breaker 1QF, the circuit breaker 2QF, the circuit breaker 3QF, the circuit breaker QF11 and the circuit breaker QF12 are all trolley-type circuit breakers.

[0012] The beneficial effects of the utility model are as follows: the high-voltage and high-power motor control system based on the frequency converter and solid-state soft starter of the utility model is provided with a soft starter and a frequency converter which serve as backup for each other to control the high-voltage and high-power motor. When the operation is mainly based on the frequency converter, when the frequency converter fails, it switches to industrial frequency operation or soft starter to start, thereby reducing the impact on the power grid; after the motor stops, the soft starter can also directly start the motor; when the operation is mainly based on the soft starter, when the soft starter fails, the frequency converter receives a fault signal, and the frequency converter will directly execute a flying start to ensure that the motor is quickly put into operation. After the motor stops, the frequency converter can also directly start the motor, thereby realizing the variable frequency or industrial frequency operation of the motor according to the needs of the site.

[0013] It can be seen that the high-voltage and high-power motor control system based on the frequency converter and solid-state soft start of the utility model, while ensuring economy, guarantees the smooth operation of the site to the maximum extent, ensures the timely input of motors or equipment, and realizes rapid response control. It can greatly improve the degree of automation of on-site control, reduce the amount of on-site maintenance, bring considerable benefits, and is worthy of vigorous promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The utility model is a circuit schematic diagram of a high-voltage and high-power motor control system based on a frequency converter and a solid-state soft starter.

[0015] In the figure: 1 soft starter, 2 frequency converter, 3 upper power circuit breaker QF, 4 circuit breaker 1QF, 5 circuit breaker 2QF, 6 circuit breaker QF11, 7 circuit breaker QF12, 8 high-voltage and high-power motor, 9 circuit breaker 3QF, 10 high-voltage AC bus, 11 buffer contactor KM2, 12 buffer resistor, 13 phase-shifting transformer, 14 inverter power unit, 15 soft starter cabinet, 16 soft starter isolation cabinet, 17 frequency converter cabinet, 18 voltage detection board. DETAILED DESCRIPTION

[0016] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0017] like Figure 1 As shown, a circuit schematic diagram of a high-voltage high-power motor control system based on a frequency converter and solid-state soft start of the utility model is given, which is composed of a soft starter 1, a frequency converter 2, an upper power circuit breaker QF, a circuit breaker 1QF, a circuit breaker 2QF, a circuit breaker 3QF, a circuit breaker QF11, a circuit breaker QF12 and a high-voltage high-power motor 8. The incoming line terminal of the upper power circuit breaker QF is connected to the high-voltage AC bus 10, and the high-voltage AC bus 10 is used to provide a high-voltage AC power supply for the operation of the high-voltage high-power motor 8. The upper power circuit breaker QF is connected to the input end of the soft starter 1 through the circuit breaker 1QF, and the output end of the soft starter 1 is connected to the power input end of the high-voltage high-power motor 8 through the circuit breaker 2QF. In this way, when the upper power circuit breaker QF, the circuit breaker 1QF and the circuit breaker 2QF are all closed, the high-voltage AC power supply can control the high-voltage high-power motor 8 to perform soft starting through the soft starter 1.

[0018] The outlet of the upper power circuit breaker QF shown is connected to the input of the frequency converter 2 via the circuit breaker QF11, and the output of the frequency converter 2 is connected to the power input of the high-voltage high-power motor 8 via the circuit breaker QF12. In this way, when the upper power circuit breaker QF, the circuit breaker QF11 and the circuit breaker QF12 are closed, the AC power provided by the high-voltage power bus 10 can control the variable frequency start or variable frequency operation of the high-voltage high-power motor 8 through the frequency converter 2. The outlet of the upper power circuit breaker QF shown is connected to the power input of the high-voltage high-power motor 8 via the circuit breaker 3QF. In this way, by closing the circuit breaker 3QF and keeping other circuit breakers in the disconnected state, the high-voltage AC power can control the high-voltage high-power motor 8 to operate at the industrial frequency state through the circuit breaker 3QF.

[0019] In order to realize buffer power-on of the frequency converter 2, the circuit breaker QF11 is connected in parallel with a power-on buffer circuit, which is composed of a buffer contactor KM2 and a buffer resistor 12. One end of the normally open point of the buffer contactor KM2 is connected to the incoming line end of the circuit breaker QF11, and the other end of the normally open point is connected to the outgoing line end of the circuit breaker QF11 through the buffer resistor 12. When the frequency converter 2 is powered on, the buffer contactor KM2 is closed first, and the frequency converter 2 is powered on through the current limiting of the buffer resistor 12. After the power-on buffering is completed, the circuit breaker QF11 is closed to supply power to the frequency converter 2.

[0020] The inverter 2 shown is composed of a phase-shifting transformer 13 and an inverter power unit 14. The input end of the phase-shifting transformer 13 forms the input end of the inverter 2, the output end of the phase-shifting transformer 13 is connected to the input end of the inverter power unit 14, and the output end of the inverter power unit 14 forms the output end of the inverter 2.

[0021] An AC transformer TA1 is provided at the input end of the inverter 2 shown, and an AC transformer TA2, an AC transformer TA3 and a voltage detection board 18 are provided at the output end of the inverter, so as to detect the current signal at the input end of the inverter 2 and the voltage and current signals at the output end when the inverter 2 controls the operation of the high-voltage and high-power motor 8.

[0022] As shown, the circuit breaker 1QF and the soft starter 1 are arranged in the soft start cabinet 15, the circuit breaker 2QF and the circuit breaker 3QF are arranged in the soft start isolation cabinet 16, and the circuit breaker QF11, the circuit breaker QF12 and the frequency converter 2 are arranged in the frequency converter cabinet 17. The circuit breaker 1QF, the circuit breaker 2QF, the circuit breaker 3QF, the circuit breaker QF11 and the circuit breaker QF12 can all adopt the trolley type circuit breaker.

[0023] The utility model is based on the inverter and solid-state soft start high-voltage high-power motor control system:

[0024] First, set the startup mode to soft start mode and send control power. At this time, the system executes the self-check logic to ensure that there is no fault, emergency stop, process permission and other conditions. Then send out the "closing permission" signal. After receiving the "closing permission" signal on site, QF closes. After QF is closed, it will feedback the "high voltage ready" signal to the system. At this time, 1QF in the soft start circuit is closed, and 2QF is closed after a delay of 1S. The solid-state soft start detects whether there is any fault inside. If there is no fault, it will send out the "system ready" signal. At this time, the on-site personnel can click to start the machine, and the motor soft start runs and sends out the "soft start running" signal.

[0025] In soft start mode, when the QF on site feeds back the "high voltage ready" signal to the control system, the inverter will also execute the internal self-check logic. After confirming that there is no fault inside the inverter, KM2 will first close for buffering, and after buffering for 3S, QF11 will close, and KM2 will be disconnected after a delay of 500ms. At this time, the inverter is in standby state and sends out a "standby ready" signal, indicating that the standby system inverter is ready to switch at any time. When a fault occurs during soft start operation, the inverter receives the soft start fault signal, 2QF circuit breaker is disconnected, QF12 is immediately closed, and the inverter uses the voltage detection board to detect the current operating frequency of the motor and quickly executes the flying process. The motor starts quickly and sends out a "frequency conversion operation" signal. At this point, the fault switching process is completed and the motor runs smoothly.

[0026] First, set the startup mode to variable frequency startup, send control power, and send out a "closing permission" signal when it is detected that the frequency conversion system itself has no faults, no emergency stops, and the process is allowed. After receiving the "closing permission" signal on site, QF can be closed, and the QF high-voltage switch cabinet will feedback the signal "high voltage ready". After the frequency converter system detects the "high voltage ready" signal, it determines that the system itself has no faults, and when all external conditions are met, KM2 is closed, and QF11 is closed after a buffer of 3S, and KM2 is disconnected after a delay of 500ms. Delay 1S to close QF12, and send out a "system ready" signal. After receiving the frequency conversion ready signal on site, click the power-on signal, the frequency converter runs and sends out a "frequency conversion operation" signal. At this point, the frequency conversion startup process is completed.

[0027] Convert to industrial frequency in variable frequency mode: The motor's operating frequency can be adjusted according to the on-site process during variable frequency operation, and the on-site frequency and current feedback signals can be given in real time. When the on-site needs to convert to industrial frequency, the inverter can be given a "convert to industrial frequency" pulse signal. At this time, the motor's frequency is increased to 50HZ, and the current voltage phase is searched. When the phases are consistent, the system first disconnects the output circuit breaker QF12, and then closes the industrial frequency circuit breaker 3QF, and the motor converts to industrial frequency.

[0028] Frequency conversion in frequency conversion mode: When operating at industrial frequency, it can be switched to frequency conversion mode according to the on-site process requirements. When frequency conversion is required on site, the frequency converter can be given a "frequency conversion" pulse signal. At this time, the frequency converter first performs the startup process to determine that the system itself has no faults and that all external conditions are met. KM2 is closed, and QF11 is closed after a buffer of 3S. KM2 is disconnected after a delay of 500ms. After waiting for 3QF to disconnect, the output circuit breaker QF12 is closed, and the frequency converter performs a flying search for the motor operating frequency. At this point, the motor frequency conversion process is completed.

[0029] Fault switching of inverter operation mode: When the QF on site feeds back the "high voltage ready" signal to the control system, the soft starter will also execute the internal self-check logic. After confirming that there is no fault inside the soft starter, 1QF is closed. At this time, the soft starter is in standby state and sends out a "standby ready" signal, indicating that the soft starter is ready to switch at any time. When a fault occurs during inverter operation, the inverter will first disconnect the circuit breaker in the loop to ensure that the fault will not be magnified, and immediately determine whether the current motor operating frequency meets the fault-to-power frequency condition. If the condition is met, it will directly switch to 3QF operation. If the switching condition is not met, the system will give the soft starter a start-up command and close 2QF. At this time, the soft starter executes the start-up, drags the motor to start and sends out a "soft start operation" signal, and the fault switching process is completed. When the fault switching is finally realized, the interference to the power grid is small, and the purpose of motor starting can still be guaranteed.

Claims

1. A high-voltage, high-power motor control system based on a frequency converter and a solid-state soft starter, comprising a high-voltage, high-power motor (8), an upper power circuit breaker QF (3), a circuit breaker 1QF (4), a circuit breaker 2QF (5), a circuit breaker QF11 (6) and a circuit breaker QF12 (7), wherein the incoming line of the upper power circuit breaker QF is connected to a high-voltage AC bus (10); characterized in that: It also includes a soft starter (1) and a frequency converter (2) which serve as backup for each other. The output terminal of the upper power circuit breaker QF is connected to the input terminal of the soft starter via the normally open point of the circuit breaker 1QF, and the output terminal of the soft starter is connected to the power input terminal of the high-voltage high-power motor via the circuit breaker 2QF; the output terminal of the upper power circuit breaker QF is connected to the input terminal of the frequency converter via the circuit breaker QF11, and the output terminal of the frequency converter is connected to the power input terminal of the high-voltage high-power motor via the circuit breaker QF12.

2. The high-voltage and high-power motor control system based on a frequency converter and solid-state soft starter according to claim 1 is characterized in that: It comprises a circuit breaker 3QF (9), the incoming line terminal of the circuit breaker 3QF is connected to the outgoing line terminal of the upper power circuit breaker QF (3), and the outgoing line terminal of the circuit breaker 3QF is connected to the power input terminal of the high-voltage and high-power motor (8).

3. The high-voltage and high-power motor control system based on a frequency converter and solid-state soft starter according to claim 1 or 2, characterized in that: The circuit breaker QF11 (6) is connected in parallel with a power-on buffer circuit, which is composed of a buffer contactor KM2 (11) and a buffer resistor (12); one end of the normally open point of the buffer contactor KM2 is connected to the incoming line terminal of the circuit breaker QF11, and the other end of the normally open point is connected to the outgoing line terminal of the circuit breaker QF11 via the buffer resistor.

4. The high-voltage and high-power motor control system based on a frequency converter and solid-state soft starter according to claim 1 or 2, characterized in that: The frequency converter (2) is composed of a phase-shifting transformer (13) and an inverter power unit (14), wherein the input end of the phase-shifting transformer forms the input end of the frequency converter, the output end of the phase-shifting transformer is connected to the input end of the inverter power unit, and the output end of the inverter power unit forms the output end of the frequency converter.

5. The high-voltage and high-power motor control system based on a frequency converter and solid-state soft starter according to claim 1 or 2, characterized in that: An AC transformer TA1 is provided at the input end of the frequency converter (2), and an AC transformer TA2, an AC transformer TA3 and a voltage detection board (18) are provided at the output end of the frequency converter.

6. The high-voltage and high-power motor control system based on a frequency converter and solid-state soft starter according to claim 2 is characterized in that: The circuit breaker 1QF (4) and the soft starter (1) are arranged in a soft start cabinet (15), the circuit breaker 2QF (5) and the circuit breaker 3QF (9) are arranged in a soft start isolation cabinet (16), and the circuit breaker QF11 (6), the circuit breaker QF12 (7) and the frequency converter (2) are arranged in a frequency converter cabinet (17).

7. The high-voltage and high-power motor control system based on a frequency converter and solid-state soft starter according to claim 2 is characterized in that: The circuit breaker 1QF (4), the circuit breaker 2QF (5), the circuit breaker 3QF (9), the circuit breaker QF11 (6) and the circuit breaker QF12 (7) are all trolley-type circuit breakers.

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