High-voltage variable-frequency speed regulation and variable-frequency soft start control circuit structure based on variable-frequency soft start

Abstract

The utility model provides a high-voltage variable-frequency speed regulation and variable-frequency soft start control circuit structure based on variable-frequency soft start, which relates to the technical field of high-voltage frequency converters and comprises a high-voltage bus, a first circuit breaker, a second circuit breaker, a third circuit breaker, a fourth circuit breaker, a fifth circuit breaker, a high-voltage variable-frequency speed regulation device, a high-voltage variable-frequency soft start device, a reactor and a high-voltage asynchronous motor. The circuit breaker I, the circuit breaker II and the circuit breaker III are connected with the high-voltage bus; the first circuit breaker is electrically connected with the high-voltage variable-frequency speed regulation device, the high-voltage variable-frequency speed regulation device is electrically connected with the fourth circuit breaker, and the fourth circuit breaker is electrically connected with the high-voltage asynchronous motor; the second circuit breaker is electrically connected with a high-voltage variable-frequency soft start device, the high-voltage variable-frequency soft start device is electrically connected with an electric reactor, the electric reactor is electrically connected with a fifth circuit breaker, and the fifth circuit breaker is electrically connected with a high-voltage asynchronous motor; and the circuit breaker III is electrically connected with the high-voltage asynchronous motor. The high-voltage variable-frequency soft start device can realize synchronous non-disturbance switching, and impact on a power grid, a motor and a motor load is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of high-voltage frequency converters, and in particular to a high-voltage frequency conversion speed regulation and frequency conversion soft start control circuit structure based on frequency conversion soft start. Background Art

[0002] With the rapid development of power electronics technology, computer and automatic control technology, AC high-voltage frequency converters have been recognized by users in various industries and confirmed by the market for their technical advantages such as significant energy-saving benefits, high speed regulation accuracy, wide speed regulation range, and complete power electronics protection functions. They have become the preferred solution for domestic and foreign companies to improve the degree of process automation, increase production efficiency, save energy, reduce consumption, and reduce user operating costs in their motor systems.

[0003] Based on the superior performance and application of the high-voltage inverter of vector control, the power of the motor is no longer "a big horse pulling a small cart". The motor can be configured according to the maximum value in the process requirements, and the high-voltage inverter of appropriate capacity can be configured according to the parameters such as the motor power. Due to the production process requirements, the reliability requirements of the motor system are very strict in important load occasions. Therefore, the manual / automatic power frequency bypass system is generally configured according to the switching time allowed by the process. The inverter controls the disconnection of the output switch, and then directly closes the power frequency switch to drive the motor directly to run. This kind of switching is asynchronous switching, and the biggest disadvantage is that it will still have a certain impact on the power grid and the motor during the switching process.

[0004] Therefore, there are areas for improvement, and the utility model provides a high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start. Utility Model Content

[0005] In view of the shortcomings of the prior art, the utility model aims to propose a high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start. The specific scheme is as follows:

[0006] A high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start, the circuit structure comprising a high-voltage bus, a circuit breaker 1, a circuit breaker 2, a circuit breaker 3, a circuit breaker 4, a circuit breaker 5, a high-voltage variable frequency speed regulation device, a high-voltage variable frequency soft start device, a reactor and a high-voltage asynchronous motor;

[0007] Among them, circuit breaker 1, circuit breaker 2, and circuit breaker 3 are first connected to the high-voltage busbar;

[0008] The circuit breaker one is electrically connected to the high-voltage frequency conversion speed regulating device, the high-voltage frequency conversion speed regulating device is electrically connected to the circuit breaker four, and the circuit breaker four is electrically connected to the high-voltage asynchronous motor;

[0009] The circuit breaker 2 is then electrically connected to the high-voltage frequency conversion soft start device, the high-voltage frequency conversion soft start device is then electrically connected to the reactor, the reactor is then electrically connected to the circuit breaker 5, and the circuit breaker 5 is then electrically connected to the high-voltage asynchronous motor;

[0010] Circuit breaker three is then electrically connected to the high-voltage asynchronous motor.

[0011] Furthermore, the high-voltage variable frequency speed regulating device is a frequency converter based on the full power configuration of the high-voltage asynchronous motor.

[0012] Furthermore, the high-voltage variable frequency soft start device is a frequency converter configured according to a load resistance torque curve and data, and the load is one third of the full power.

[0013] Furthermore, circuit breaker 1, circuit breaker 2, circuit breaker 3, circuit breaker 4, and circuit breaker 5 are all draw-out vacuum circuit breakers.

[0014] Furthermore, when the high-voltage asynchronous motor needs to operate with variable frequency, the high-voltage variable frequency speed regulation device receives the start command, controls the closing of circuit breaker one, and the high-voltage variable frequency speed regulation device is powered on with high voltage. The self-inspection is ready, there is no alarm, and there is no fault. The high-voltage variable frequency speed regulation device then controls the closing of circuit breaker four. Finally, the high-voltage variable frequency speed regulation device adjusts the given frequency according to the production process requirements to drive the high-voltage asynchronous motor to operate with variable frequency.

[0015] Furthermore, when the high-voltage variable frequency speed regulating device fails, the circuit breaker 4 and the circuit breaker 1 are controlled to be opened, and the high-voltage variable frequency speed regulating device exits;

[0016] After receiving the command to cut the power frequency, the high-voltage frequency conversion soft-start device controls circuit breaker two to close, and the high-voltage frequency conversion soft-start device is powered on at high voltage. The self-check is ready, there is no alarm, and there is no fault. The high-voltage frequency conversion soft-start device then controls circuit breaker five to close, and automatically runs to the power frequency of 50Hz. The high-voltage frequency conversion soft-start device automatically detects the phase, voltage, frequency and other parameters of the high-voltage asynchronous motor and power supply system, and then locks the phase. When the switching requirements are met, the circuit breaker three is controlled to close, and the high-voltage asynchronous motor is switched to power frequency operation. The circuit breaker five and circuit breaker two are controlled to open, and the high-voltage frequency conversion soft-start device exits.

[0017] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0018] The high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure involved in the utility model is used in important load occasions. A set of spare high-voltage variable frequency soft start devices and related hardware such as reactors and circuit breakers are added to the conventional high-voltage variable frequency drive control circuit, so that each high-voltage variable frequency drive can drive the corresponding motor to operate as a speed regulation device under normal circumstances. When the high-voltage variable frequency speed regulation device fails, the spare high-voltage variable frequency soft start device is used to start the high-voltage asynchronous motor of the load through switch switching, so as to realize the disturbance-free synchronous switching from variable frequency to industrial frequency, and the high-voltage asynchronous motor is driven by industrial frequency to operate, thereby greatly improving the reliability and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a circuit diagram of an embodiment of the utility model.

[0020] Figure numerals: 1. high-voltage busbar; 2. circuit breaker one; 3. circuit breaker two; 4. circuit breaker three; 5. circuit breaker four; 6. circuit breaker five; 7. high-voltage frequency conversion speed regulation device; 8. high-voltage frequency conversion soft start device; 9. reactor; 10. high-voltage asynchronous motor. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below in conjunction with the embodiments and drawings, but the implementation methods of the present invention are not limited thereto.

[0022] The utility model provides a high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start, adds a set of spare variable frequency soft start device, reactor 9 and switch hardware in the conventional high-voltage frequency converter control circuit, adjusts the control algorithm logic so that it can complete the automatic input or removal of the variable frequency soft start circuit in the circuit according to relevant instructions, and realizes that a high-voltage frequency converter with full power configuration is used as a speed regulation device to drive the corresponding motor to operate normally.

[0023] It should be noted that when the frequency converter used for speed regulation fails, the standby high-voltage frequency conversion soft start device 8 is put into use to achieve synchronous disturbance-free switching, avoiding the electrical impact on the power grid and the motor caused by asynchronous switching of the frequency converter or direct starting of the motor, as well as the mechanical impact on the motor load, and greatly improving the reliability and safety of the entire motor drive system.

[0024] like Figure 1 As shown, the circuit structure includes a high-voltage bus 1, a circuit breaker 1 2, a circuit breaker 2 3, a circuit breaker 3 4, a circuit breaker 4 5, a circuit breaker 5 6, a high-voltage frequency conversion speed regulation device 7, a high-voltage frequency conversion soft start device 8, a reactor 9 and a high-voltage asynchronous motor 10.

[0025] exist Figure 1In the figure, QF1 is circuit breaker one 2; QF2 is circuit breaker two 3; QF3 is circuit breaker three 4; QF11 is circuit breaker four 5; QF12 is circuit breaker five 6; VFD1 is high-voltage variable frequency speed regulation device 7; VFD2 is high-voltage variable frequency soft start device 8; L is reactor 9; M is high-voltage asynchronous motor 10.

[0026] Specifically, QF1 uses a withdrawable vacuum circuit breaker to provide power to the frequency converter VFD1;

[0027] QF2 uses a withdrawable vacuum circuit breaker to provide power to the frequency converter VFD2;

[0028] QF3 uses a withdrawable vacuum circuit breaker to provide industrial frequency power to the motor;

[0029] QF11 uses a withdrawable vacuum circuit breaker, which is the outgoing line switch of the frequency converter VFD1;

[0030] QF12 uses a withdrawable vacuum circuit breaker, which is the outgoing line switch of the frequency converter VFD2;

[0031] VFD1 uses a high-voltage variable frequency speed regulating device 7 configured according to the full power of the high-voltage asynchronous motor 10, and when in use, it will communicate with the background DCS;

[0032] VFD2 uses a light-power high-voltage variable frequency soft start device 8 configured according to the load resistance moment curve and data, and will communicate with the background DCS when in use. For example, the general fan and pump load is only one-third of the full power. In this embodiment, the load corresponding to VFD2 is also one-third of the full power.

[0033] L is a reactor 9, which is used to limit the power grid circulating current when the frequency converter switches to the power frequency, so as to avoid the impact on the frequency converter and the power grid.

[0034] M is a high voltage asynchronous motor 10.

[0035] When making specific connections, the circuit breaker 1 2, the circuit breaker 2 3, and the circuit breaker 3 4 are first connected to the high-voltage bus 1;

[0036] The circuit breaker 1 2 is then electrically connected to the high-voltage frequency conversion speed regulating device 7, the high-voltage frequency conversion speed regulating device 7 is then electrically connected to the circuit breaker 4 5, and the circuit breaker 4 5 is then electrically connected to the high-voltage asynchronous motor 10;

[0037] The circuit breaker 2 3 is then electrically connected to the high-voltage frequency conversion soft start device 8, the high-voltage frequency conversion soft start device 8 is then electrically connected to the reactor 9, the reactor 9 is then electrically connected to the circuit breaker 5 6, and the circuit breaker 5 6 is then electrically connected to the high-voltage asynchronous motor 10;

[0038] The circuit breaker three 4 is then electrically connected to the high-voltage asynchronous motor 10.

[0039] Based on the above circuit structure, its operation logic is as follows:

[0040] When the high-voltage asynchronous motor 10 needs to run at variable frequency, the background DCS sends a start command. After the high-voltage frequency conversion speed regulating device 7 receives the start command, it controls the circuit breaker 1 2 to close, and the high-voltage frequency conversion speed regulating device 7 is powered on at high voltage. After self-checking, it is ready, there is no alarm, and there is no fault. The high-voltage frequency conversion speed regulating device 7 then controls the circuit breaker 4 5 to close. Finally, the high-voltage frequency conversion speed regulating device 7 adjusts the given frequency according to the production process requirements to drive the high-voltage asynchronous motor 10 to run at variable frequency.

[0041] When the high-voltage variable frequency speed regulating device 7 fails, the circuit breaker 4 5 and the circuit breaker 1 2 are controlled to be opened, and the high-voltage variable frequency speed regulating device 7 exits;

[0042] After receiving the command to cut the power frequency, the high-voltage frequency conversion soft-start device 8 controls the circuit breaker two 3 to close, the high-voltage frequency conversion soft-start device 8 is powered on at high voltage, and the self-check is ready, there is no alarm, and there is no fault. The high-voltage frequency conversion soft-start device 8 then controls the circuit breaker five 6 to close, and automatically runs to the power frequency of 50Hz. The high-voltage frequency conversion soft-start device 8 automatically detects the phase, voltage, frequency and other parameters of the high-voltage asynchronous motor 10 and the power supply system, and then locks the phase. When the switching requirements are met, the circuit breaker three 4 is controlled to close, and the high-voltage asynchronous motor 10 switches to the power frequency operation. The circuit breaker five 6 and the circuit breaker two 3 are controlled to open, and the high-voltage frequency conversion soft-start device 8 exits.

[0043] The above is only a preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start, characterized in that: The circuit structure comprises a high-voltage busbar (1), a circuit breaker 1 (2), a circuit breaker 2 (3), a circuit breaker 3 (4), a circuit breaker 4 (5), a circuit breaker 5 (6), a high-voltage variable frequency speed regulating device (7), a high-voltage variable frequency soft start device (8), a reactor (9) and a high-voltage asynchronous motor (10); Wherein, circuit breaker 1 (2), circuit breaker 2 (3), and circuit breaker 3 (4) are first connected to the high-voltage busbar (1); The circuit breaker 1 (2) is then electrically connected to the high-voltage frequency conversion speed regulating device (7), the high-voltage frequency conversion speed regulating device (7) is then electrically connected to the circuit breaker 4 (5), and the circuit breaker 4 (5) is then electrically connected to the high-voltage asynchronous motor (10); The circuit breaker 2 (3) is then electrically connected to the high-voltage frequency conversion soft start device (8), the high-voltage frequency conversion soft start device (8) is then electrically connected to the reactor (9), the reactor (9) is then electrically connected to the circuit breaker 5 (6), and the circuit breaker 5 (6) is then electrically connected to the high-voltage asynchronous motor (10); The circuit breaker three (4) is then electrically connected to the high voltage asynchronous motor (10).

2. The high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start according to claim 1 is characterized in that: The high-voltage frequency conversion speed regulating device (7) is a frequency converter based on the full-power configuration of the high-voltage asynchronous motor (10).

3. The high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start according to claim 2 is characterized in that: The high-voltage frequency conversion soft start device (8) is a frequency converter configured according to a load resistance torque curve and data, and the load is one third of the full power.

4. The high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start according to claim 3 is characterized in that: Circuit breaker 1 (2), circuit breaker 2 (3), circuit breaker 3 (4), circuit breaker 4 (5) and circuit breaker 5 (6) are all draw-out vacuum circuit breakers.

5. The high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start according to claim 1 is characterized in that: When the high-voltage asynchronous motor (10) needs to be operated at variable frequency, the high-voltage variable frequency speed regulating device (7) receives a start command and controls the first circuit breaker (2) to be closed, the high-voltage variable frequency speed regulating device (7) is powered on at high voltage, self-checks and is ready, with no alarm or fault, and then controls the fourth circuit breaker (5) to be closed. Finally, the high-voltage variable frequency speed regulating device (7) adjusts the given frequency according to the production process requirements to drive the high-voltage asynchronous motor (10) to operate at variable frequency.

6. The high-voltage variable frequency speed regulation and variable frequency soft start control circuit structure based on variable frequency soft start according to claim 5 is characterized in that: When the high-voltage variable frequency speed regulating device (7) fails, the circuit breaker four (5) and the circuit breaker one (2) are controlled to open, and the high-voltage variable frequency speed regulating device (7) exits; After receiving the command to cut the power frequency, the high-voltage frequency conversion soft start device (8) controls the circuit breaker two (3) to close, the high-voltage frequency conversion soft start device (8) is powered on at high voltage, self-checks and is ready, with no alarm or fault. The high-voltage frequency conversion soft start device (8) then controls the circuit breaker five (6) to close, and automatically runs to the power frequency of 50 Hz. The high-voltage frequency conversion soft start device (8) automatically detects the phase, voltage and frequency parameters of the high-voltage asynchronous motor (10) and the power system, and then locks the phase. When the switching requirements are met, the circuit breaker three (4) is controlled to close, the high-voltage asynchronous motor (10) is switched to power frequency operation, the circuit breaker five (6) and the circuit breaker two (3) are controlled to open, and the high-voltage frequency conversion soft start device (8) exits.

Images