A combined variable frequency starter

Abstract

The present disclosure discloses a combined variable frequency starter, including a main control module, which is used to receive and send control instructions; a variable frequency module, which is electrically connected to the main control module and includes a rectifier unit, a filter unit and an inverter unit connected in sequence, wherein the rectifier unit includes a plurality of rectifiers connected in parallel, the filter unit is used to perform a filtering operation on the current input from the rectifier unit, and the inverter unit includes a plurality of inverter circuits connected in parallel; an industrial frequency module, which is connected to the main control module and includes multiple industrial frequency circuits, wherein each industrial frequency circuit is used to start a control circuit; a lighting comprehensive protection module, which is connected to the industrial frequency module and is used to perform a voltage reduction process on the power provided by the industrial frequency module and provide circuit protection for related lines and loads. The combined variable frequency starter provided by this solution can not only provide sufficient driving force, but also occupies a small volume, has simple connections between modules, and is easy to troubleshoot when a fault occurs.

Description

Technical Field

[0001] The present disclosure generally relates to the field of variable frequency technology. More specifically, the present disclosure relates to a combined variable frequency starter. Background Art

[0002] The inverter is mainly composed of rectification, filtering, inversion, braking unit, drive unit, detection unit, microprocessor unit, etc. The inverter adjusts the voltage and frequency of the output power supply by opening and closing the internal insulated gate bipolar transistor (full name in English, "IGBT"), and provides the required power supply voltage according to the actual needs of the motor, thereby achieving the purpose of energy saving and speed regulation. In addition, the inverter has many protection functions, such as over-current, over-voltage, overload protection, etc. It is mainly used in industries such as electricity, metallurgy, cement, petrochemicals and building materials.

[0003] In the mining field, the frequency converter commonly used is the explosion-proof and intrinsically safe frequency converter for mining. In the actual working process, there will be a need to add supporting auxiliary equipment to the aforementioned explosion-proof and intrinsically safe frequency converter for mining. For example, in some scenarios, the supporting auxiliary equipment includes the cutter head of a full-face tunnel boring machine (full English name, "TBM") and special lighting comprehensive protection equipment. However, since the existing explosion-proof and intrinsically safe frequency converter for mining is only equipped with one rectification, filtering and inverter on the explosion-proof casing, it can usually only drive one or more frequency conversion motors, which is not enough to drive the supporting auxiliary equipment.

[0004] In addition, if the existing inverter is to drive the auxiliary equipment and lighting circuit, it is necessary to add a feed switch and a special lighting comprehensive protection device. However, adding such multiple devices not only occupies a large volume, but also the connection between each device is complicated, and it is not easy to troubleshoot when a fault occurs.

[0005] In view of this, there is an urgent need to provide a combined variable frequency starter so that it can not only connect auxiliary equipment such as lighting and comprehensive protection, but also provide sufficient driving force for subsequent supporting equipment. Utility Model Content

[0006] In order to at least solve one or more of the technical problems mentioned above, the present disclosure proposes a combined variable frequency starter integrating an industrial frequency module and a lighting comprehensive protection module, which not only reduces the occupied volume of the equipment, but also can provide sufficient driving force for the motor.

[0007] Specifically, the present disclosure provides a combined variable frequency starter, including: a main control module, which is used to receive and send control instructions; a frequency conversion module, which is electrically connected to the main control module and includes a rectifier unit, a filter unit and an inverter unit connected in sequence, wherein the rectifier unit includes a plurality of rectifier parts connected in parallel, the rectifier part is used to convert the input alternating current into direct current, the filter unit is used to perform a filtering operation on the direct current input from the rectifier unit, and the inverter unit includes a plurality of inverter circuits connected in parallel, the inverter circuit is used to convert the direct current after the filtering operation into alternating current, wherein the inverter unit is connected in parallel with the filter unit; an industrial frequency module, which is connected to the main control module and includes multiple industrial frequency circuits, wherein each industrial frequency circuit is used to start the control circuit; a lighting comprehensive protection module, which is connected to the industrial frequency module and is used to perform voltage reduction processing on the power provided by the industrial frequency module and provide circuit protection for related lines and loads.

[0008] In some embodiments, the power frequency module includes m large power frequency loops and n small power frequency loops, where m and n are both positive integers not less than 1.

[0009] In some embodiments, a resistance-capacitance absorption unit is provided on the power frequency circuit, which is used to absorb high-order harmonics generated in the power frequency circuit.

[0010] In some embodiments, a DC bus is also included, wherein a plurality of rectifiers in the rectifier unit and a plurality of inverter circuits on the inverter unit are output to the DC bus together.

[0011] In some embodiments, each inverter circuit in the inverter unit is also connected to an inverter auxiliary control unit corresponding thereto, wherein the inverter auxiliary control unit is used to send information and process signals.

[0012] In some embodiments, the inverter auxiliary control unit includes a digital signal processing circuit and an auxiliary control circuit that are connected to each other, wherein the digital signal processing circuit is connected to the inverter circuit, and the auxiliary control circuit is connected to the main control module; the digital signal processing circuit collects current, voltage and / or temperature; the auxiliary control circuit sends the information detected by the digital signal processing unit to the main control module, and sends the set output frequency, maximum current and / or torque to the digital signal processing unit.

[0013] In some embodiments, the power frequency circuit has a pilot unit, and the pilot unit is used to prevent the starting signal of the motor connected to the power frequency module from malfunctioning or sticking, so as to ensure the smooth operation of the motor.

[0014] In some embodiments, the lighting comprehensive protection module includes an isolating switch, a transformer, a contactor and a short-circuit breaker; the isolating switch is arranged at the entrance of the lighting comprehensive protection circuit, and is used to cut off or connect the power supply to control the flow of power supply; the transformer is connected after the isolating switch, and is used to convert the high-voltage power supply into a low-voltage power supply; the contactor and the short-circuit breaker are connected after the transformer, and are used to control and protect the multi-channel output power supply after voltage reduction, wherein the contactor is used to control the connection and disconnection of the circuit, and the short-circuit breaker is used to cut off the power supply when the circuit is short-circuited.

[0015] In some embodiments, the power frequency circuit is connected to the main control module to provide power input to the main control module.

[0016] In some embodiments, the combined variable frequency starter includes a plurality of chambers surrounded by a shell for placing different modules, and the high frequency module and the industrial frequency module are placed in different chambers.

[0017] Through the combined frequency conversion starter provided as above, the disclosed embodiment not only adjusts the rectifier unit, filter unit and inverter unit of the frequency conversion module, but also integrates the power frequency module, so as to provide sufficient driving force for the subsequent supporting equipment. And because the combined frequency conversion starter also integrates the lighting comprehensive protection module, it can perform voltage reduction processing on the power supply of the power frequency module, and can also provide circuit protection for related lines and loads. Further, in some embodiments, a resistor-capacitor absorption unit is provided on the power frequency circuit to absorb the high-order harmonics generated in the power frequency circuit. Furthermore, the multiple rectifier units in the rectifier unit and the multiple inverter circuits on the inverter unit are output to the DC bus together, so that when the combined frequency conversion starter is running, the DC bus voltage is more stable and the operating output waveform is smoother. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] By reading the detailed description below with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0019] Figure 1 An exemplary structural block diagram of a combined variable frequency starter according to an embodiment of the present disclosure is shown;

[0020] Figure 2 An exemplary structural block diagram of a frequency conversion module according to an embodiment of the present disclosure is shown;

[0021] Figure 3 An exemplary structural block diagram of the power frequency module of the embodiment of the present disclosure is shown;

[0022] Figure 4A circuit diagram of a rectifier unit and a filter unit on the power frequency module disclosed in the present invention is shown;

[0023] Figure 5 A circuit diagram of a part of the inverter unit on the power frequency module disclosed in the present invention is shown;

[0024] Figure 6 A circuit diagram of a large industrial frequency circuit on the frequency conversion module disclosed in the present invention is shown;

[0025] Figure 7 A circuit diagram of a small industrial frequency loop on the frequency conversion module disclosed herein is shown.

[0026] In the figure: 100, combined variable frequency starter;

[0027] 101. Main control module; 102. Frequency conversion module; 103. Power frequency module; 104. Lighting comprehensive protection module;

[0028] 201, rectifier unit; 202, filter unit; 203, inverter unit; 204, disconnector;

[0029] 2011, rectifier; 2031, inverter circuit;

[0030] 301, large industrial frequency circuit; 302, small industrial frequency circuit. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0032] It should be understood that the terms "include" and "comprising" used in the specification and claims of the present disclosure indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0033] It should also be understood that the terms used in this disclosure are only for the purpose of describing specific embodiments and are not intended to limit the disclosure. As used in this disclosure and claims, the singular forms of "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in this disclosure and claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations.

[0034] As used in this specification and claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0035] The specific implementation of the present disclosure is described in detail below with reference to the accompanying drawings.

[0036] Exemplary application scenarios

[0037] Figure 1-Figure 7 A combined variable frequency starter 100 is shown, comprising a main control module 101, which is used to receive and send control instructions; a variable frequency module 102, which is electrically connected to the main control module 101 and comprises a rectifier unit 201, a filter unit 202 and an inverter unit 203 connected in sequence, wherein the rectifier unit 201 comprises a plurality of rectifier units 2011 connected in parallel, the rectifier unit 2011 is used to convert the input alternating current into direct current, the filter unit 202 is used to perform a filtering operation on the direct current input from the rectifier unit 201, and the inverter unit 203 is used to filter the direct current input from the rectifier unit 201. 03 includes a plurality of inverter circuits 2031 connected in parallel, and the inverter circuit 2031 is used to convert the DC power after filtering operation into AC power, wherein the inverter unit 203 is connected in parallel with the filtering unit 202; an industrial frequency module 103, which is connected to the main control module 101 and includes a plurality of industrial frequency circuits, wherein each industrial frequency circuit is used to start the control circuit; a lighting comprehensive protection module 104, which is connected to the industrial frequency module 103, and is used to perform voltage reduction processing on the power provided by the industrial frequency module 103 and provide circuit protection for related lines and loads.

[0038] The combined variable frequency starter 100 provided in this solution has a lighting comprehensive protection module 104, so there is no need to provide a lighting comprehensive protection device thereafter. Also, since the power frequency module 103 is provided, when the variable frequency module 102 drives the motor to reach full speed but still fails to meet the requirements, the motor is switched to the power frequency module 103 for operation.

[0039] Example 1

[0040] In view of this, an embodiment of the present disclosure provides a combined variable frequency starter.

[0041] The combined variable frequency starter 100 includes: a main control module 101, which is used to receive and send control instructions; a variable frequency module 102, which is electrically connected to the main control module 101 and includes a rectifier unit 201, a filter unit 202 and an inverter unit 203 connected in sequence, wherein the rectifier unit 201 includes a plurality of rectifier units 2011 connected in parallel, the rectifier unit 2011 is used to convert the input alternating current into direct current, the filter unit 202 is used to perform a filtering operation on the direct current input from the rectifier unit 201, and the inverter unit 203 is used to filter the direct current input from the rectifier unit 201. It includes a plurality of inverter circuits 2031 connected in parallel, and the inverter circuit 2031 is used to convert the DC power after filtering operation into AC power, wherein the inverter unit 203 is connected in parallel with the filtering unit 202; an industrial frequency module 103, which is connected to the main control module 101 and includes a plurality of industrial frequency circuits, wherein each industrial frequency circuit is used to start the control circuit; a lighting comprehensive protection module 104, which is connected to the industrial frequency module 103 and is used to perform voltage reduction processing on the power provided by the industrial frequency module 103 and provide circuit protection for related lines and loads.

[0042] The inverter adjusts the voltage and frequency of the output power supply by the internal IGBT switching, and provides the required power supply voltage according to the actual needs of the motor, thereby achieving the purpose of energy saving and speed regulation. The traditional inverter is mainly composed of a frequency conversion module, a brake module, a drive module, a detection module, and a microprocessor module. The frequency conversion module includes a rectifier 1, a filter, and an inverter circuit 3 connected in sequence. Among them, the function of the rectifier 1 is to convert the input AC power into DC power, the function of the filter is to filter the DC power, and the function of the inverter circuit 3 is to convert the DC power after the filter operation into AC power.

[0043] like Figure 1 and Figure 2 As shown, the combined frequency conversion starter 100 provided in this embodiment is based on the traditional frequency converter, the frequency conversion module 102 is adjusted, and the lighting comprehensive protection module 104 and the industrial frequency module 103 are integrated to form a new combined frequency conversion starter 100. Specifically, the rectification in the frequency conversion module 102 in this embodiment is no longer a single circuit, but a rectification unit 201 formed by a plurality of rectifiers 2011 connected in parallel. The inverter circuit 2031 is no longer just one circuit, but an inverter unit 203 formed by a plurality of inverter circuits 2031 connected in parallel. The filtering is no longer the traditional small-capacity filtering, but a filter unit 202 with an increased capacity.

[0044] like Figure 4 and Figure 5As shown, in a specific scheme of the present embodiment, the rectifier unit 201 includes twelve rectifier parts 2011 connected in parallel, the inverter unit 203 is connected in parallel to the filter circuit, and six inverter circuits 2031 are connected in parallel as needed. In order to cooperate with the rectifier unit and the inverter unit, the capacity of the filter unit is also increased in this scheme. When in use, the current of the six rectifier parts 2011 in the rectifier unit 201 is fed into the reactor and the main contactor through an isolating switch 204. After the pre-charging circuit is charged, the main contactor is energized, and the current is converted into a direct current through the rectifier bridge and enters the filter module to perform filtering operations and store, and then enters the inverter module for inversion. The main function of the reactor is to absorb the high-order harmonics generated in the input and output circuits of the frequency conversion module 102 during the inversion process, thereby avoiding interference of high-order harmonics to the power supply system, loads and other adjacent electrical equipment. Figure 5 Only three inverter circuits are shown.

[0045] The combined frequency conversion starter 100 in this solution also includes an industrial frequency module 103 and a lighting comprehensive protection module 104. The industrial frequency module 103 includes a plurality of industrial frequency circuits for starting control circuits. The lighting comprehensive protection module 104 is connected to the industrial frequency module 103, and includes a transformer and a special protection device. The transformer can perform voltage reduction processing on the power provided by the industrial frequency module 103. The protection device can protect against possible faults such as lack of phase, short circuit, overvoltage, overload, and phase imbalance. In this solution, the industrial frequency module 103 and the frequency conversion module 102 are both connected to the main control module 101, and the main control module 101 includes a PLC controllable programmable controller, an intrinsically safe power supply, an intermediate relay, an analog conversion circuit, a communication conversion module, and an input signal circuit and an output display processing circuit, so as to realize various control functions such as switching between the industrial frequency module 103 and the frequency conversion module 102 in the combined frequency conversion starter 100. For example, when the frequency conversion module 102 cannot drive the subsequent matching equipment, the main control module 101 can switch the frequency conversion module 102 to the industrial frequency module 103 to control the operation of the subsequent matching equipment.

[0046] The combined variable frequency starter 100 in this solution includes a plurality of chambers surrounded by a shell for placing different modules. In order to prevent the signals of the variable frequency module 102 and the power frequency module 103 from affecting each other, the variable frequency module 102 and the power frequency module 103 are placed in different chambers.

[0047] The solution of this embodiment also includes: the frequency conversion module 102 has a DC bus, wherein the multiple rectification parts 2011 in the rectification unit 201 and the multiple inverter circuits 2031 on the inverter unit 203 are output to the DC bus together.

[0048] In the solution of this embodiment, the multiple rectifiers 2011 connected in parallel in the rectifier unit 201 are output to a DC bus, and the multiple inverter circuits 2031 connected in parallel on the inverter unit 203 are also connected to the DC bus. Since the frequency conversion module 102 in the combined variable frequency starter adopts a common DC bus design, when the combined variable frequency starter is running, the DC bus voltage is more stable and the operating output waveform is smoother.

[0049] The solution of this embodiment also includes: each inverter circuit 2031 in the inverter unit 203 is also connected to an inverter auxiliary control unit corresponding thereto, wherein the inverter auxiliary control unit is used to send information and process signals. The inverter auxiliary control unit includes a digital signal processing circuit and an auxiliary control circuit connected to each other, wherein the digital signal processing circuit is connected to the inverter circuit 2031, and the auxiliary control circuit is connected to the main control module 101; the digital signal processing circuit collects current, voltage and / or temperature; the auxiliary control circuit sends the information detected by the digital signal processing circuit to the main control module 101, and sends the set output frequency, maximum current and / or torque to the digital signal processing circuit.

[0050] In the scheme of this embodiment, each inverter circuit 2031 in the inverter unit 203 is also connected to an inverter auxiliary control unit for sending information and processing signals. The inverter unit 203 described above has six inverter circuits 2031, and each inverter circuit 2031 is connected to an inverter auxiliary control unit. The inverter auxiliary control unit includes a digital signal processing circuit connected by communication, and the digital signal processing circuit can collect variable information such as current, voltage and temperature, and pre-process the above variable information. The digital signal processing circuit also includes an optical fiber distribution board and an interface board, wherein the optical fiber distribution board is used to receive information from the main control module 101, generate a drive signal, and control the conduction and shutdown of the power module. The inverter auxiliary control unit also includes an auxiliary control circuit connected to the digital signal processing circuit. The auxiliary control circuit has a built-in communication module, which can send the DC bus voltage, module temperature, output current, and communication status detected by the digital signal processing circuit to the main control module 101. It can also send information such as the set output frequency, maximum current, and torque to the auxiliary control circuit.

[0051] The power frequency module 103 includes m-way large power frequency circuits 301 and n-way small power frequency circuits 302, wherein m and n are both positive integers not less than 1. The power frequency circuit is provided with a resistance-capacitance absorption unit, which is used to absorb the higher harmonics generated in the power frequency circuit. The power frequency circuit has a pilot unit, which is a pilot circuit, and a single-chip microcomputer is provided in the pilot circuit, and a diode is provided between the two ends. The pilot circuit plays the role of isolating the input control signal to prevent the control circuit from being connected in a short-circuit state and causing the device to start accidentally.

[0052] like Figure 6 and Figure 7 As shown, in the scheme of this embodiment, the power frequency module 103 includes multiple large power frequency circuits 301 and multiple small power frequency circuits 302. Since there are many fields where frequency converters are applicable, in order to enable the combined variable frequency starter 100 to be used on a shield machine, the power frequency module 103 is designed to have four large power frequency circuits 301 and eight small power frequency circuits 302. This design can not only meet the needs of the shield machine, but also effectively reduce the occupied space of the combined variable frequency starter 100. Of course, in other specific schemes, the number of large power frequency circuits 301 and the number of small power frequency circuits 302 on the power frequency module 103 are also set according to the different needs of different equipment.

[0053] In this solution, in order to avoid noise caused by high-order harmonics generated by the power frequency circuit, a resistance-capacitance absorption unit for absorbing high-order harmonics is specially provided on the four-way large power frequency circuit 301 and the eight-way small power frequency circuit 302, thereby avoiding damage to the combined frequency converter caused by high-order harmonics. The combined frequency conversion starter 100 is usually connected to the motor when in use. In order to prevent the starting signal of the motor from malfunctioning or sticking when starting, a pilot unit is provided on the four-way large power frequency circuit 301 and the eight-way small power frequency circuit 302 on the power frequency module 103, thereby ensuring that the motor can run smoothly.

[0054] The solution of this embodiment also includes: the lighting comprehensive protection module 104 includes an isolating switch, a transformer, a contactor and a short circuit device; the isolating switch is set at the entrance of the lighting comprehensive protection circuit, and is used to cut off or connect the power supply to control the flow of the power supply; the transformer is connected after the isolating switch, and is used to convert the high-voltage power supply into a low-voltage power supply; the contactor and the short circuit device are connected after the transformer, and are used to control and protect the multi-channel output power supply after the voltage is stepped down, wherein the contactor is used to control the connection and disconnection of the circuit, and the short circuit device is used to cut off the power supply when the circuit is short-circuited. The power frequency circuit is connected to the main control module 101 to provide power input to the main control module 101.

[0055] In this solution, the lighting comprehensive protection module 104 has an isolating switch, a transformer, a contactor and a short circuit breaker. The isolating switch is arranged at the entrance of the lighting comprehensive protection circuit, and is used to cut off or connect the power supply according to the demand. The transformer in the lighting comprehensive protection circuit is a step-down device, which is arranged after the isolating switch, and is used to step down the 1140V power supply to obtain a 127V output power supply. The contactor and the short circuit breaker are connected after the step-down device, and are used to control and protect the multi-channel output power supply after the step-down, wherein the contactor is used to control the connection and disconnection of the circuit, and the short circuit breaker is used to cut off the power supply when the circuit is short-circuited. In a specific solution of this embodiment, the 1140V power supply on the lighting comprehensive protection module circuit passes through the isolating switch on the lighting comprehensive protection circuit to the transformer in turn, and outputs 6 127V output power supplies through the contactor and the short circuit breaker. The output power after step-down is connected to the power frequency circuit on the power frequency module 103. In addition, the lighting comprehensive protection circuit also has a special protection device to protect possible faults such as phase loss, short circuit, overvoltage, overload, and phase imbalance.

[0056] In a specific implementation of this embodiment, the power frequency circuit on the power frequency module 103 is connected to the main control module 101 to provide power input to the main control module 101. In other words, the power supply of the main control module 101 is the 127V low-voltage electricity after the power frequency circuit on the power frequency module 103 is stepped down.

[0057] The solution provided in this embodiment forms a combined frequency conversion starter 100 by integrating the main control module 101, the frequency conversion module 102, the lighting comprehensive protection module 104 and the industrial frequency module 103 in a plurality of chambers surrounded by a shell for placing different modules. The combined frequency conversion starter 100 can not only provide sufficient driving force for subsequent supporting equipment, but also occupies a small volume, has simple connections between modules, and is easy to troubleshoot when a fault occurs.

[0058] Although multiple embodiments of the present disclosure have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may think of many changes, modifications, and alternatives without departing from the thought and spirit of the present disclosure. It should be understood that in the process of practicing the present disclosure, various alternatives to the embodiments of the present disclosure described herein may be adopted. The attached claims are intended to define the scope of protection of the present disclosure, and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A combined variable frequency starter, characterized in that: include: A main control module, which is used to receive and send control instructions; A frequency conversion module, which is electrically connected to the main control module and includes a rectifier unit, a filter unit and an inverter unit connected in sequence, wherein the rectifier unit includes a plurality of rectifiers connected in parallel, the rectifiers are used to convert the input AC power into DC power, the filter unit is used to perform a filtering operation on the DC power input from the rectifier unit, the inverter unit includes a plurality of inverter circuits connected in parallel, the inverter circuit is used to convert the DC power after the filtering operation into AC power, wherein the inverter unit is connected in parallel with the filter unit; A power frequency module, which is connected to the main control module and includes multiple power frequency circuits, wherein each power frequency circuit is used to start a control circuit; The lighting comprehensive protection module is connected to the power frequency module and is used to perform voltage reduction processing on the power provided by the power frequency module and provide circuit protection for related lines and loads.

2. The combined variable frequency starter according to claim 1, characterized in that: The power frequency module includes m large power frequency loops and n small power frequency loops, wherein m and n are both positive integers not less than 1.

3. The combined variable frequency starter according to claim 1 or 2, characterized in that: The power frequency circuit is provided with a resistance-capacitance absorption unit, which is used to absorb the high-order harmonics generated in the power frequency circuit.

4. The combined variable frequency starter according to claim 3, characterized in that: It also includes a DC bus, wherein a plurality of rectifiers in the rectifier unit and a plurality of inverter circuits on the inverter unit are output to the DC bus together.

5. The combined variable frequency starter according to claim 4, characterized in that: Each inverter circuit in the inverter unit is also connected to an inverter auxiliary control unit corresponding thereto, wherein the inverter auxiliary control unit is used to send information and process signals.

6. The combined variable frequency starter according to claim 5, characterized in that: The inverter auxiliary control unit comprises a digital signal processing circuit and an auxiliary control circuit connected to each other, wherein the digital signal processing circuit is connected to the inverter circuit, and the auxiliary control circuit is connected to the main control module; The digital signal processing circuit collects current, voltage and / or temperature; The auxiliary control circuit sends the information detected by the digital signal processing circuit to the main control module, and sends the set output frequency, maximum current and / or torque to the digital signal processing circuit.

7. The combined variable frequency starter according to claim 1, characterized in that: The power frequency circuit is provided with a pilot unit, and the pilot unit is used to prevent the starting signal of the motor connected to the power frequency module from malfunctioning or sticking, so as to make the motor run smoothly.

8. The combined variable frequency starter according to claim 1, characterized in that: The lighting comprehensive protection module includes an isolating switch, a transformer, a contactor and a short-circuit breaker; the isolating switch is arranged at the entrance of the lighting comprehensive protection circuit, and is used to cut off or connect the power supply to control the flow of power supply; the transformer is connected after the isolating switch, and is used to convert the high-voltage power supply into a low-voltage power supply; the contactor and the short-circuit breaker are connected after the transformer, and are used to control and protect the multi-channel output power supply after voltage reduction, wherein the contactor is used to control the connection and disconnection of the circuit, and the short-circuit breaker is used to cut off the power supply when the circuit is short-circuited.

9. The combined variable frequency starter according to claim 1, characterized in that: The power frequency circuit is connected to the main control module to provide power input to the main control module.

10. The combined variable frequency starter according to any one of claims 1 to 9, characterized in that: The combined variable frequency starter comprises a plurality of chambers surrounded by a shell for placing different modules, and the high frequency module and the industrial frequency module are placed in different chambers.

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