Frequency conversion and soft start combined control system

Abstract

A frequency conversion and soft start combined control system comprises a main loop and a control loop, and is technically characterized in that the main loop comprises a frequency converter FC1, a frequency converter FC2, a soft start controller, a motor M1 and a motor M2, and the frequency converter FC1 is connected with the motor M1 through a normally open contact 1KM1-1 of a contactor 1KM1; the frequency converter FC2 is connected with the motor M2 through a normally open contact 2KM1-1 of the contactor 2KM1; the soft start controller is connected with the motor M1 through a normally open contact 1KM2-1 of the contactor 1KM2 and connected with the motor M2 through a normally open contact 2KM2-1 of the contactor 2KM2, the normally open contact 1KM2-1 of the contactor 1KM2 is connected with the normally open contact 1KM1-1 of the contactor 1KM1 in parallel, and the normally open contact 2KM2-1 of the contactor 2KM2 is connected with the normally open contact 2KM1-1 of the contactor 2KM1 in parallel. According to the utility model, through a frequency conversion one-dragging-one-soft-start one-dragging-two setting mode, the operation mode of the device can be freely switched between frequency conversion control and soft start control, the two motors are adopted to work alternately to guarantee the operation of the device, and meanwhile, a manual control mode and an automatic control mode are set to meet the operation and control requirements of workers.

Description

Technical field:

[0001] The utility model relates to the field of industrial automation control, in particular to a variable frequency soft start combined control system. Background technology:

[0002] In existing industrial control systems, the operating requirements of control equipment are often more complex. Sometimes it is necessary to adjust the speed of equipment operation, and sometimes it is necessary to start and stop equipment smoothly, which increases the requirements for the control system. In addition, in actual work, it is not realistic to require staff to monitor and operate the running equipment 24 hours a day, and at the same time, supervisory and management personnel must be set up to monitor and guide the staff's operation, and the monitoring management personnel cannot stay by the running equipment at any time. Especially for control equipment located outdoors or even in the open field, such as oil pumps, this type of control equipment greatly increases the labor intensity of the staff. And for high-intensity operating equipment, the loss and requirements of the motor are very large. Once the motor fails, the entire equipment will be shut down, and the maintenance of the motor will inevitably take time. This phenomenon not only affects the service life of the motor, but also brings serious losses to the equipment shutdown, and even serious safety hazards.

[0003] Therefore, for control equipment with complex industrial control and complex requirements, it is particularly critical to set up a reasonable control system that combines the above functions and requirements and overcomes the above defects. Summary of the invention:

[0004] The purpose of the utility model is to provide a variable frequency soft start combined control system, which enables the equipment to switch the operating mode between variable frequency control and soft start control at will through the setting mode of one-to-one variable frequency and one-to-two soft start, and adopts two motors to work alternately to ensure the operation of the equipment. At the same time, the manual control and automatic control modes are set to meet the control needs of the staff.

[0005] The utility model of variable frequency soft start joint control system includes a main circuit and a control circuit, and the technical solution adopted is:

[0006] The main circuit includes a frequency converter FC1, a frequency converter FC2, a soft start controller, a motor M1 and a motor M2. The frequency converter FC1 is connected to the motor M1 via the normally open contact 1KM1-1 of the contactor 1KM1; the frequency converter FC2 is connected to the motor M2 via the normally open contact 2KM1-1 of the contactor 2KM1; the soft start controller is connected to the motor M1 via the normally open contact 1KM2-1 of the contactor 1KM2, and is connected to the motor M2 via the normally open contact 2KM2-1 of the contactor 2KM2. The normally open contact 1KM2-1 of the contactor 1KM2 is connected in parallel with the normally open contact 1KM1-1 of the contactor 1KM1, and the normally open contact 2KM2-1 of the contactor 2KM2 is connected in parallel with the normally open contact 2KM1-1 of the contactor 2KM1;

[0007] The control loop includes a motor M1 control loop and a motor M2 control loop.

[0008] The motor M1 control circuit and the motor M2 control circuit respectively include a frequency conversion control circuit, a soft start control circuit, a manual-automatic conversion switch, a frequency conversion soft start conversion switch and a PLC1 switch. The frequency conversion control circuit and the soft start control circuit are connected in parallel with each other.

[0009] The frequency conversion control circuit includes a frequency conversion automatic control circuit and a frequency conversion manual control circuit connected in parallel with each other, and the soft start control circuit includes a soft start automatic control circuit and a soft start manual control circuit connected in parallel with each other.

[0010] The PLC start switch is connected to the automatic position of the manual-automatic conversion switch QK1 and then connected in series with the variable frequency automatic control circuit and the soft start automatic control circuit.

[0011] The manual gear of the manual-automatic conversion switch is connected in series with the variable frequency manual control circuit and the soft start manual control circuit respectively.

[0012] In some preferred embodiments of the present invention, the frequency conversion control circuit in the motor M1 control circuit includes a contactor 1KM1 and a start button 1SB2.

[0013] The PLC1 start switch is connected in series with the coil of the contactor 1KM1 through the frequency conversion control gear of the frequency conversion soft start conversion switch SA1 to form a frequency conversion automatic control loop;

[0014] The manual gear of the manual-automatic conversion switch QK1 is connected to the normally open contact 1KM1-2 of the contactor 1KM1 through the variable frequency control gear of the variable frequency soft start conversion switch SA1, and then connected in series with the coil of the contactor 1KM1 to form a variable frequency manual control circuit.

[0015] The normally open contact 1KM1-2 of the contactor 1KM1 is connected in parallel with the start button 1SB2 and then connected in series with the coil of the contactor 1KM1.

[0016] In some other preferred embodiments of the present invention, the frequency conversion control circuit in the motor M2 control circuit includes a contactor 2KM1 and a start button 2SB2.

[0017] The PLC2 start switch is connected in series with the coil of the contactor 2KM1 through the frequency conversion control gear of the frequency conversion soft start conversion switch SA2 to form a frequency conversion automatic control loop;

[0018] The manual gear of the manual-automatic conversion switch QK2 is connected to the normally open contact 2KM1-2 of the contactor 2KM1 through the variable frequency control gear of the variable frequency soft start conversion switch SA2, and then connected in series with the coil of the contactor 2KM1 to form a variable frequency manual control circuit.

[0019] The normally open contact 2KM1-2 of the contactor 2KM1 is connected in parallel with the start button 2SB2 and then connected in series with the coil of the contactor 2KM1.

[0020] In some other preferred embodiments of the present invention, the soft start control circuit in the motor M1 control circuit includes a contactor 1KM2 and a start button 1SB4.

[0021] The PLC1 start switch is connected in series with the coil of the contactor 1KM1 through the soft start control gear of the variable frequency soft start control switch SA1 to form a soft start automatic control circuit;

[0022] The manual gear of the manual-automatic conversion switch QK1 is connected to the normally open contact 1KM2-2 of the contactor 1KM2 through the soft start control gear of the variable frequency soft start conversion switch SA1, and then connected in series with the coil of the contactor 1KM2 to form a soft start manual control circuit.

[0023] The normally open contact 1KM2-2 of the contactor 1KM2 is connected in parallel with the start button 1SB4 and then connected in series with the coil of the contactor 1KM2.

[0024] The normally open contact 1KM2-1 of the contactor 1KM2 is connected to the motor M1 and is connected in parallel with the normally open contact 1KM1-1 of the contactor 1KM1.

[0025] In some other preferred embodiments of the present invention, the soft start control circuit in the motor M2 control circuit includes a contactor 2KM2 and a start button 2SB4.

[0026] The PLC2 start switch is connected in series with the coil of the contactor 2KM1 through the soft start control gear of the variable frequency soft start control switch SA2 to form a soft start automatic control circuit;

[0027] The manual gear of the manual-automatic conversion switch QK2 is connected to the normally open contact 2KM2-2 of the contactor 2KM2 through the soft start control gear of the variable frequency soft start conversion switch SA2, and then connected in series with the coil of the contactor 2KM2 to form a soft start manual control circuit.

[0028] The normally open contact 2KM2-2 of the contactor 2KM2 is connected in parallel with the start button 2SB4 and then connected in series with the coil of the contactor 2KM2.

[0029] The normally open contact 2KM2-1 of the contactor 2KM2 is connected to the motor M2 and is connected in parallel with the normally open contact 2KM1-1 of the contactor 2KM1.

[0030] In some other preferred embodiments of the present invention, the two ends of the coil of the contactor 1KM1 are connected in parallel with the coil of the repeater 1KA2.

[0031] In some other preferred embodiments of the present invention, the two ends of the coil of the contactor 2KM1 are connected in parallel with the coil of the repeater 2KA2.

[0032] In other preferred embodiments of the present invention, the two ends of the coil of the contactor 1KM2 are connected in parallel with the coil of the repeater 1KA3, the normally open contact 1KM2-2 of the contactor 1KM2, the start button 1SB4 and the normally open contact 1KA3 of the repeater 1KA3 are connected in parallel with each other and then connected in series with the coil of the contactor 1KM2 and the coil of the repeater 1KA3.

[0033] In other preferred embodiments of the present invention, the two ends of the coil of the contactor 2KM2 are connected in parallel with the coil of the repeater 2KA3, the normally open contact 2KM2-2 of the contactor 2KM2, the start button 2SB4 and the normally open contact 2KA3 of the repeater 2KA3 are connected in parallel with each other and then connected in series with the coil of the contactor 2KM2 and the coil of the repeater 2KA3.

[0034] In some other preferred embodiments of the present invention, the control circuit includes a soft start bypass, and the soft start bypass includes a contactor KM3, a soft start indicator light 1HG2 and a soft start contact KB. The coil of the contactor KM3 and the soft start indicator light 1HG2 are connected in parallel and then in series with the soft start contact KB.

[0035] The two ends of the soft start controller are connected in parallel with the normally open contact KM3-1 of the contactor KM3, and the normally open contact KM3-1 of the contactor KM3 is connected in series with the normally open contact 1KM2-1 of the contactor 1KM2 and the normally open contact 2KM2-1 of the contactor 2KM2 respectively.

[0036] The variable frequency soft start combined control system of the utility model has the following beneficial effects:

[0037] 1. The utility model is provided with a frequency conversion control system and a soft start control system, which can switch between the frequency conversion control and the soft start control at will, and two motors are provided, and one of the motors can be started at will to operate the equipment according to the on-site requirements. Using two motors to work alternately in this way can extend the service life of the motors, and at the same time has a working mode of one backup and one use. When one of the motors fails and cannot operate, the other motor can be started to ensure the normal operation of the equipment. Specifically, two frequency converters control the start and stop of the two motors respectively, and the soft start controller directly controls the start and stop of the two motors, realizing a control mode of one frequency conversion and one soft start and two soft start, that is, a frequency converter controls the start and stop of one motor, and a soft start controller controls the start and stop of two motors. The frequency converter can adjust the running speed of the motor, and the soft start controller can make the motor start and stop smoothly to meet the different use requirements of the control equipment.

[0038] 2. On the basis of frequency conversion control and soft start control, the utility model further sets manual start control and automatic start control in each control mode, namely frequency conversion manual control and frequency conversion automatic control, soft start manual control and soft start automatic control. This makes it convenient for staff and managers to control the operation of the equipment at different locations, reduces the labor intensity and difficulty of staff and managers, and meets the use requirements of the equipment. Description of the drawings:

[0039] Figure 1 It is the main circuit diagram of the utility model;

[0040] Figure 2 It is the control circuit diagram of the motor M1 in the utility model;

[0041] Figure 3 It is a control loop circuit diagram of the motor M2 in the utility model. Specific implementation method:

[0042] The following is an explanation of the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0043] The variable frequency soft start joint control system in this embodiment includes a main circuit and a control circuit. Figure 1As shown, the main circuit includes a frequency converter FC1, a frequency converter FC2, a soft start controller, a motor M1 and a motor M2. The frequency converter FC1 is connected to the motor M1 via the normally open contact 1KM1-1 of the contactor 1KM1; the frequency converter FC2 is connected to the motor M2 via the normally open contact 2KM1-1 of the contactor 2KM1; the soft start controller is connected to the motor M1 via the normally open contact 1KM2-1 of the contactor 1KM2, and is connected to the motor M2 via the normally open contact 2KM2-1 of the contactor 2KM2. The normally open contact 1KM2 of the contactor 1KM 2-1 is connected in parallel with the normally open contact 1KM1-1 of contactor 1KM1, and the normally open contact 2KM2-1 of contactor 2KM2 is connected in parallel with the normally open contact 2KM1-1 of contactor 2KM1; in this way, the start and stop of motor M1 is controlled by frequency converter FC1, the start and stop of motor M2 is controlled by frequency converter FC2, and the start and stop of motor M1 and motor M2 are directly controlled by soft start controller, realizing the control mode of one-to-one frequency conversion (i.e., one frequency converter controls the start and stop of one motor) and one-to-two soft start (i.e., one soft start controller controls the start and stop of two motors).

[0044] like Figure 2 and Figure 3 As shown, the control loop includes a motor M1 control loop and a motor M2 control loop.

[0045] The motor M1 control circuit and the motor M2 control circuit respectively include a frequency conversion control circuit, a soft start control circuit, a manual-automatic conversion switch, a frequency conversion soft start conversion switch and a PLC start switch. The frequency conversion control circuit and the soft start control circuit are connected in parallel.

[0046] The frequency conversion control circuit includes a frequency conversion automatic control circuit and a frequency conversion manual control circuit connected in parallel with each other, and the soft start control circuit includes a soft start automatic control circuit and a soft start manual control circuit connected in parallel with each other.

[0047] The PLC1 start switch is connected to the automatic position of the manual-automatic conversion switch QK1 and then connected in series with the variable frequency automatic control circuit and the soft start automatic control circuit.

[0048] The manual gear of the manual-automatic conversion switch is connected in series with the variable frequency manual control circuit and the soft start manual control circuit respectively.

[0049] The frequency conversion control circuit in the motor M1 control circuit includes a contactor 1KM1 and a start button 1SB2.

[0050] The PLC1 start switch is connected in series with the coil of the contactor 1KM1 through the frequency conversion control gear of the frequency conversion soft start conversion switch SA1 to form a frequency conversion automatic control loop;

[0051] The manual gear of the manual-automatic conversion switch QK1 is connected to the normally open contact 1KM1-2 of the contactor 1KM1 through the variable frequency control gear of the variable frequency soft start conversion switch SA1, and then connected in series with the coil of the contactor 1KM1 to form a variable frequency manual control circuit.

[0052] The normally open contact 1KM1-2 of the contactor 1KM1 is connected in parallel with the start button 1SB2 and then connected in series with the coil of the contactor 1KM1.

[0053] Reference Figure 2 When starting with variable frequency, turn the manual automatic conversion switch QK1 to the automatic position, turn the variable frequency soft start conversion switch SA1 to the automatic variable frequency control position, the remote control system controls the PLC1 start switch to close, and the coil of the contactor 1KM1 to close. Figure 1 , its normally open contact 1KM1-1 is closed, and the frequency converter FC1 is connected to the motor M1 to realize the variable frequency automatic start of the motor M1; refer to Figure 2 When starting with manual frequency conversion, turn the manual-automatic conversion switch QK1 to the manual position, turn the frequency conversion soft start conversion switch SA1 to the frequency conversion control position, press the start button 1SB2, the coil of the contactor 1KM1 is energized, and its normally open contact 1KM1-2 is attracted to form a self-locking so that its coil is continuously energized. Figure 1 , its normally open contact 1KM1-1 is closed, and the frequency converter FC1 is connected to the motor M1 to realize the variable frequency manual starting of the motor M1.

[0054] like Figure 2 As shown, the soft start control circuit in the motor M1 control circuit includes a contactor 1KM2 and a start button 1SB4.

[0055] The PLC start switch is connected in series with the coil of the contactor 1KM1 through the soft start control gear of the variable frequency soft start control switch SA1 to form a soft start automatic control circuit;

[0056] The manual gear of the manual-automatic conversion switch QK1 is connected to the normally open contact 1KM2-2 of the contactor 1KM2 through the soft start control gear of the variable frequency soft start conversion switch SA1, and then connected in series with the coil of the contactor 1KM2 to form a soft start manual control circuit. The normally open contact 1KM2-2 of the contactor 1KM2 is connected in parallel with the start button 1SB4 and then connected in series with the coil of the contactor 1KM2. Figure 1 As shown, the normally open contact 1KM2-1 of the contactor 1KM2 is connected to the motor M1 and is connected in parallel with the normally open contact 1KM1-1 of the contactor 1KM1.

[0057] like Figure 2As shown, when manual soft start is performed, turn the manual-automatic conversion switch QK1 to the manual gear, turn the variable frequency soft start conversion switch SA1 to the soft start control gear, press the start button 1SB4, the coil of the contactor 1KM2 is energized, and its normally open contact 1KM2-2 is attracted to form a self-locking so that its coil is continuously energized. Figure 1 , its normally open contact 1KM2-1 is closed, the soft start controller is connected to the motor M1, and the manual soft start of the motor M1 is realized; refer to Figure 2 When performing automatic soft start, turn the manual automatic conversion switch QK1 to the automatic gear, turn the frequency conversion soft start conversion switch SA1 to the automatic soft start control gear, the remote control system controls the PLC1 start switch to close, and the coil of the contactor 1KM2 to close. Figure 1 , its normally open contact 1KM2-1 is closed, and the soft start controller is connected to the motor M1 to realize automatic soft start of the motor M1.

[0058] In some preferred embodiments,

[0059] like Figure 3 As shown, the frequency conversion control circuit in the motor M2 control circuit includes a contactor 2KM1 and a start button 2SB2, and the PLC2 start switch is connected in series with the coil of the contactor 2KM1 through the frequency conversion control gear of the frequency conversion soft start conversion switch SA2 to form a frequency conversion automatic control circuit;

[0060] The manual gear of the manual-automatic conversion switch QK2 is connected to the normally open contact 2KM1-2 of the contactor 2KM1 through the frequency control gear of the frequency conversion soft start conversion switch SA2, and then connected in series with the coil of the contactor 2KM1 to form a frequency conversion manual control circuit. The normally open contact 2KM1-2 of the contactor 2KM1 is connected in parallel with the start button 2SB2 and then connected in series with the coil of the contactor 2KM1.

[0061] Reference Figure 3 When starting with manual frequency conversion, turn the manual-automatic conversion switch QK2 to the manual position, turn the frequency conversion soft start conversion switch SA2 to the frequency conversion control position, press the start button 2SB2, the coil of the contactor 2KM1 is energized, and its normally open contact 2KM1-2 is attracted to form a self-locking so that its coil is continuously energized. Figure 1 , its normally open contact 2KM1-1 is closed, and the frequency converter FC2 is connected to the motor M2 to realize the manual frequency conversion start of the motor M2; refer to Figure 3 When starting with automatic frequency conversion, turn the manual automatic conversion switch QK2 to the automatic gear, turn the frequency conversion soft start conversion switch SA2 to the automatic frequency conversion control gear, the remote control system controls the PLC2 start switch to close, and the coil of the contactor 2KM1 to close. Figure 1 , its normally open contact 2KM1-1 is closed, and the frequency converter FC2 is connected to the motor M2 to realize automatic frequency conversion starting of the motor M2.

[0062] Reference Figure 3 , the soft start control circuit in the motor M2 control circuit includes a contactor 2KM2 and a start button 2SB4, and the PLC2 start switch is connected in series with the coil of the contactor 2KM1 through the soft start control gear of the variable frequency soft start control switch SA2 to form a soft start automatic control circuit;

[0063] The manual gear of the manual-automatic conversion switch QK2 is connected to the normally open contact 2KM2-2 of the contactor 2KM2 through the soft start control gear of the variable frequency soft start conversion switch SA2, and then connected in series with the coil of the contactor 2KM2 to form a soft start manual control circuit. The normally open contact 2KM2-2 of the contactor 2KM2 is connected in parallel with the start button 2SB4 and then connected in series with the coil of the contactor 2KM2. Figure 1 As shown, the normally open contact 2KM2-1 of the contactor 2KM2 is connected to the motor M2 and is connected in parallel with the normally open contact 2KM1-1 of the contactor 2KM1.

[0064] Reference Figure 3 When manual soft start is performed, turn the manual-automatic conversion switch QK2 to the manual position, turn the variable frequency soft start conversion switch SA2 to the soft start control position, press the start button 2SB4, the coil of the contactor 2KM2 is energized, and its normally open contact 2KM2-2 is attracted to form a self-locking so that its coil is continuously energized. Figure 1 , its normally open contact 2KM2-1 is closed, the soft start controller is connected to the motor M2, and the manual soft start of the motor M2 is realized; refer to Figure 3 When performing automatic soft start, turn the manual automatic conversion switch QK2 to the automatic gear, turn the variable frequency soft start conversion switch SA2 to the automatic variable frequency control gear, the remote control system controls the PLC2 start switch to close, and the coil of the contactor 2KM2 to close. Figure 3 , its normally open contact 2KM2-1 is closed, and the soft start controller is connected to the motor M2 to realize automatic soft start of the motor M2.

[0065] In some preferred embodiments, Figure 2 As shown, the two ends of the coil of the contactor 1KM1 are connected in parallel with the coil of the relay 1KA2. Figure 1 , its normally open contact 1KM1-1 is energized, and the motor M1 starts running. Figure 2 At this time, the coil of repeater 1KA2 is energized, and repeater 1KA2 sends a signal to the remote control system indicating that motor M1 is in the variable frequency control operation state, thus forming a variable frequency control state signal.

[0066] In some preferred embodiments, Figure 2As shown, the two ends of the coil of the contactor 1KM2 are connected in parallel with the coil of the repeater 1KA3. The normally open contact 1KM2-2 of the contactor 1KM2, the start button 1SB4 and the normally open contact 1KA3 of the repeater 1KA3 are connected in parallel and then connected in series with the coil of the contactor 1KM2 and the coil of the repeater 1KA3. Figure 1 , its normally open contact 1KM2-1 is energized, and the motor M1 starts running. Figure 2 At this time, the coil of repeater 1KA3 is energized, and repeater 1KA3 sends a signal to the remote control system indicating that motor M1 is in the soft start control operation state, thus forming a soft start control state signal.

[0067] In some preferred embodiments, Figure 3 As shown, the two ends of the coil of the contactor 2KM1 are connected in parallel with the coil of the relay 2KA2. Figure 1 , its normally open contact 2KM1-1 is energized, and the motor M2 starts running. Figure 3 At this time, the coil of repeater 2KA2 is energized, and repeater 2KA2 sends a signal to the remote control system indicating that motor M2 is in the variable frequency control operation state, thus forming a variable frequency control state signal.

[0068] In some preferred embodiments, Figure 3 As shown, the two ends of the coil of the contactor 2KM2 are connected in parallel with the coil of the repeater 2KA3. The normally open contact 2KM2-2 of the contactor 2KM2, the start button 2SB4 and the normally open contact 2KA3 of the repeater 2KA3 are connected in parallel and then connected in series with the coil of the contactor 2KM2 and the coil of the repeater 2KA3. Figure 1 , its normally open contact 2KM2-1 is energized, and the motor M2 starts running. Figure 3 At this time, the coil of repeater 2KA3 is energized, and repeater 2KA3 sends a signal to the remote control system indicating that motor M2 is in the soft start control operation state, thus forming a soft start control state signal.

[0069] In some preferred embodiments, Figure 1 As shown, the control circuit includes a soft start bypass, and the soft start bypass includes a contactor KM3, a soft start indicator light 1HG2 and a soft start contact KB. The coil of the contactor KM3 and the soft start indicator light 1HG2 are connected in parallel and then in series with the soft start contact KB. The two ends of the soft start controller are connected in parallel with the normally open contact KM3-1 of the contactor KM3. The normally open contact KM3-1 of the contactor KM3 is connected in series with the normally open contact 1KM2-1 of the contactor 1KM2 and the normally open contact 2KM2-1 of the contactor 2KM2. Figure 2 or Figure 3 When the soft-start contact KB of the soft-start controller is closed, the coil of contactor KM3 is energized, and its normally open contact KM3-1 is closed, and then the normally open contact 1KM2-1 of contactor 1KM2 or the normally open contact 2KM2-1 of contactor 2KM2 is closed to directly control the start and stop of motor M1 or motor M2. In this way, the soft-start controller is bypassed, and motor M1 or motor M2 is started directly by the power supply. In this way, motor M1 or motor M2 is started and stopped by the soft-start bypass.

[0070] In some preferred embodiments, the frequency conversion control circuit is provided with a normally closed contact 2KM1-3 of the contactor 2KM1 connected in series with the coil of the contactor 1KM1. When the coil of the contactor 2KM1 is energized, the normally closed contact 2KM1-3 of the contactor 2KM1 is disconnected to ensure that the coil of the contactor 1KM1 remains de-energized. Figure 1 , its normally open contact 1KM1-1 is de-energized, so that an interlock is formed between the normally open contact 1KM1-2 of contactor 1KM1 and the normally open contact 2KM1-2 of contactor 2KM1, thereby ensuring that motor M1 remains in a de-energized stopped state and ensuring that only one of motor M1 and motor M2 can start.

[0071] Similarly, further, in some preferred embodiments, such as Figure 1 As shown, the normally closed contact 2KM2-3 of contactor 2KM2 is connected in series next to the coil of contactor 1KM1, and the normally closed contact 2KM1-4 of contactor 2KM1 and the normally closed contact 2KM2-4 of contactor 2KM2 are connected in series next to the coil of contactor 1KM2; the normally closed contact 2KM2-4, the normally closed contact 1KM1-3 of contactor 1KM1, and the normally closed contact 1KM2-3 of contactor 1KM2 are connected in series next to the coil of contactor 2KM1; the normally closed contact 2KM1-4, the normally closed contact 1KM1-4 of contactor 1KM1, and the normally closed contact 1KM2-4 of contactor 1KM2 are connected in series next to the coil of contactor 2KM2. Such design is to ensure that motor M1 and motor M2 can only ensure that one motor is in the starting and running state under the variable frequency or soft starting state.

[0072] In some preferred embodiments, Figure 1 As shown, the control circuit includes a soft start fault indication circuit, which includes a repeater 1KA4, a fault indicator light 1HY2 and a soft start fault contact RQ. The repeater 1KA4 and the fault indicator light 1HY2 are connected in parallel and then in series with the soft start fault contact RQ. When a fault occurs in the soft start controller, its soft start fault contact RQ is closed, the coil of the repeater 1KA4 is energized, and fault information is sent to the control system as a soft start fault state signal. At the same time, the fault indicator light 1HY2 lights up, so that the staff can see the fault indication in time.

[0073] Similarly, a frequency conversion fault circuit and a frequency conversion operation circuit may also be provided in the control circuit of the motor M1. The frequency conversion fault circuit is provided with a coil of a repeater 1KA1, which is connected in parallel with the frequency conversion fault indicator light 1HY1 and then in series with the normally open contact FC1-1 of the frequency converter. When the frequency converter FC1-1 itself fails, its normally open contact FC1-1 is closed, the coil of the repeater 1KA1 is energized, and a fault signal of the frequency converter is sent to the remote control system. At the same time, the frequency conversion fault indicator light 1HY1 lights up, indicating that the frequency converter is in a fault state. When the frequency converter FC1 operates normally, the normally open contact FC1-2 of the frequency converter FC1 is closed, and the operation indicator light 1HG1 lights up, indicating that the frequency converter FC1 is in a normal operating state.

[0074] The variable frequency operation circuit is provided with a variable frequency operation indicator light 1HG1, which is connected in series with the normally open contact FC1 of the frequency converter to form a variable frequency operation circuit.

[0075] Similarly, a frequency conversion fault circuit and a frequency conversion operation circuit may be provided in the control circuit of the motor M2. The frequency conversion fault circuit is provided with a coil of a relay 2KA1, which is connected in parallel with the frequency conversion fault indicator light 2HY1 and then in series with the normally open contact FC2 of the frequency converter.

[0076] The variable frequency operation circuit is provided with a variable frequency operation indicator light 2HG1, which is connected in series with the normally open contact FC2 of the frequency converter to form a variable frequency operation circuit.

[0077] In some preferred embodiments, an emergency stop button 1SB1 is provided in the variable frequency manual control circuit of the motor M1, and the emergency stop button 1SB1 is provided at the input end of the circuit in parallel with the start button 1SB2 and the normally open contact 1KM1-2 of the contactor 1KM1. When a safety accident occurs and the equipment needs to stop running immediately, the emergency stop button 1SB1 can be pressed immediately to cut off the contactor 1KM1, and its normally open contact 1KM1-1 loses power, and the motor M1 stops running.

[0078] Similarly, an emergency stop button 2SB1 is provided in the variable frequency manual control circuit of the motor M2, and the emergency stop button 2SB1 is provided at the input end of the circuit in parallel with the start button 2SB2 and the normally open contact 2KM1-2 of the contactor 2KM1. When a safety accident occurs and the equipment needs to stop running immediately, the emergency stop button 2SB1 can be pressed immediately to cut off the contactor 2KM1, and its normally open contact 2KM1-1 loses power, and the motor M2 stops running.

[0079] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A variable frequency soft start joint control system, comprising a main circuit and a control circuit, characterized in that: The main circuit includes a frequency converter FC1, a frequency converter FC2, a soft start controller, a motor M1 and a motor M2. The frequency converter FC1 is connected to the motor M1 via the normally open contact 1KM1-1 of the contactor 1KM1; the frequency converter FC2 is connected to the motor M2 via the normally open contact 2KM1-1 of the contactor 2KM1; the soft start controller is connected to the motor M1 via the normally open contact 1KM2-1 of the contactor 1KM2, and is connected to the motor M2 via the normally open contact 2KM2-1 of the contactor 2KM2. The normally open contact 1KM2-1 of the contactor 1KM2 is connected in parallel with the normally open contact 1KM1-1 of the contactor 1KM1, and the normally open contact 2KM2-1 of the contactor 2KM2 is connected in parallel with the normally open contact 2KM1-1 of the contactor 2KM1; The control loop includes a motor M1 control loop and a motor M2 control loop. The motor M1 control circuit and the motor M2 control circuit respectively include a frequency conversion control circuit, a soft start control circuit, a manual-automatic conversion switch, a frequency conversion soft start conversion switch and a PLC1 switch. The frequency conversion control circuit and the soft start control circuit are connected in parallel with each other. The frequency conversion control circuit includes a frequency conversion automatic control circuit and a frequency conversion manual control circuit connected in parallel with each other, and the soft start control circuit includes a soft start automatic control circuit and a soft start manual control circuit connected in parallel with each other. The PLC start switch is connected to the automatic position of the manual-automatic conversion switch QK1 and then connected in series with the variable frequency automatic control circuit and the soft start automatic control circuit. The manual gear of the manual-automatic conversion switch is connected in series with the variable frequency manual control circuit and the soft start manual control circuit respectively.

2. A variable frequency soft start combined control system as claimed in claim 1, characterized in that: The frequency conversion control circuit in the motor M1 control circuit includes a contactor 1KM1 and a start button 1SB2. The PLC1 start switch is connected in series with the coil of the contactor 1KM1 through the frequency conversion control gear of the frequency conversion soft start conversion switch SA1 to form a frequency conversion automatic control loop; The manual gear of the manual-automatic conversion switch QK1 is connected to the normally open contact 1KM1-2 of the contactor 1KM1 through the variable frequency control gear of the variable frequency soft start conversion switch SA1, and then connected in series with the coil of the contactor 1KM1 to form a variable frequency manual control circuit. The normally open contact 1KM1-2 of the contactor 1KM1 is connected in parallel with the start button 1SB2 and then connected in series with the coil of the contactor 1KM1.

3. A variable frequency soft start combined control system as claimed in claim 1, characterized in that: The frequency conversion control circuit in the motor M2 control circuit includes a contactor 2KM1 and a start button 2SB2. The PLC2 start switch is connected in series with the coil of the contactor 2KM1 through the frequency conversion control gear of the frequency conversion soft start conversion switch SA2 to form a frequency conversion automatic control loop; The manual gear of the manual-automatic conversion switch QK2 is connected to the normally open contact 2KM1-2 of the contactor 2KM1 through the variable frequency control gear of the variable frequency soft start conversion switch SA2, and then connected in series with the coil of the contactor 2KM1 to form a variable frequency manual control circuit. The normally open contact 2KM1-2 of the contactor 2KM1 is connected in parallel with the start button 2SB2 and then connected in series with the coil of the contactor 2KM1.

4. A variable frequency soft start combined control system as claimed in claim 1, characterized in that: The soft start control circuit in the motor M1 control circuit includes a contactor 1KM2 and a start button 1SB4. The PLC1 start switch is connected in series with the coil of the contactor 1KM1 through the soft start control gear of the variable frequency soft start control switch SA1 to form a soft start automatic control circuit; The manual gear of the manual-automatic conversion switch QK1 is connected to the normally open contact 1KM2-2 of the contactor 1KM2 through the soft start control gear of the variable frequency soft start conversion switch SA1, and then connected in series with the coil of the contactor 1KM2 to form a soft start manual control circuit. The normally open contact 1KM2-2 of the contactor 1KM2 is connected in parallel with the start button 1SB4 and then connected in series with the coil of the contactor 1KM2. The normally open contact 1KM2-1 of the contactor 1KM2 is connected to the motor M1 and is connected in parallel with the normally open contact 1KM1-1 of the contactor 1KM1.

5. A variable frequency soft start combined control system as claimed in claim 3, characterized in that: The soft start control circuit in the motor M2 control circuit includes a contactor 2KM2 and a start button 2SB4. The PLC2 start switch is connected in series with the coil of the contactor 2KM1 through the soft start control gear of the variable frequency soft start control switch SA2 to form a soft start automatic control circuit; The manual gear of the manual-automatic conversion switch QK2 is connected to the normally open contact 2KM2-2 of the contactor 2KM2 through the soft start control gear of the variable frequency soft start conversion switch SA2, and then connected in series with the coil of the contactor 2KM2 to form a soft start manual control circuit. The normally open contact 2KM2-2 of the contactor 2KM2 is connected in parallel with the start button 2SB4 and then connected in series with the coil of the contactor 2KM2. The normally open contact 2KM2-1 of the contactor 2KM2 is connected to the motor M2 and is connected in parallel with the normally open contact 2KM1-1 of the contactor 2KM1.

6. A variable frequency soft start combined control system as claimed in claim 2, characterized in that: The two ends of the coil of the contactor 1KM1 are connected in parallel with the coil of the repeater 1KA2.

7. A variable frequency soft start combined control system as claimed in claim 3, characterized in that: The two ends of the coil of the contactor 2KM1 are connected in parallel with the coil of the repeater 2KA2.

8. A variable frequency soft start combined control system as claimed in claim 4, characterized in that: The two ends of the coil of the contactor 1KM2 are connected in parallel with the coil of the repeater 1KA3. The normally open contact 1KM2-2 of the contactor 1KM2, the start button 1SB4 and the normally open contact 1KA3 of the repeater 1KA3 are connected in parallel with each other and then connected in series with the coil of the contactor 1KM2 and the coil of the repeater 1KA3.

9. A variable frequency soft start combined control system as claimed in claim 5, characterized in that: The two ends of the coil of the contactor 2KM2 are connected in parallel with the coil of the repeater 2KA3. The normally open contact 2KM2-2 of the contactor 2KM2, the start button 2SB4 and the normally open contact 2KA3 of the repeater 2KA3 are connected in parallel with each other and then connected in series with the coil of the contactor 2KM2 and the coil of the repeater 2KA3.

10. A variable frequency soft start combined control system as claimed in claim 4, characterized in that: The control circuit includes a soft start bypass, which includes a contactor KM3, a soft start indicator light 1HG2 and a soft start contact KB. The coil of the contactor KM3 and the soft start indicator light 1HG2 are connected in parallel and then in series with the soft start contact KB. The two ends of the soft start controller are connected in parallel with the normally open contact KM3-1 of the contactor KM3, and the normally open contact KM3-1 of the contactor KM3 is connected in series with the normally open contact 1KM2-1 of the contactor 1KM2 and the normally open contact 2KM2-1 of the contactor 2KM2 respectively.

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