Three-level high-voltage combined frequency converter

Abstract

The utility model provides a three-level high-voltage combined frequency converter. The three-level high-voltage combined frequency converter comprises a charging part, a rectification part, a capacitance part, an inversion part and an output part, the charging part is connected with the rectification part through an input reactor, two identical energy storage output loops which are connected in parallel are connected in series behind the rectification part, each energy storage output loop comprises a capacitor part, an inversion part and an output part, the capacitor part comprises an energy storage filter capacitor, the inversion part comprises an inversion module IGBT and a driving control loop, and the driving control loop is connected with the rectification part. The output part comprises an output reactor and an output contactor, and the output part is connected with a load; according to the utility model, a three-level hardware topology structure is adopted, so that the working modes of different motors can be met; due to the modular design of each part, flexible personalized customization can be realized by configuring different communication expansion cards and comprehensive expansion cards; the stability of the frequency converter used in the underground coal mine is obviously improved, the failure rate is greatly reduced, the size is small, the cost is low, and the frequency converter is convenient to transfer.

Description

Technical Field

[0001] The utility model belongs to the technical field of mining electromechanical equipment, relates to frequency conversion speed regulation of mining equipment, and is specifically a three-level high-voltage combined frequency converter. Background Art

[0002] At present, the motors of belt conveyors, scraper conveyors, fans, water pumps and other equipment in coal mines basically use variable frequency switches, which have the advantages of energy saving, small starting current, large low-speed torque, and convenient speed regulation. However, the high-voltage frequency converters currently used in coal mines are often large in size, have a high failure rate, are inconvenient for on-site maintenance, have a short service life, and cannot be stably controlled. Utility Model Content

[0003] The purpose of the utility model is to provide a three-level high-voltage combined inverter, which can meet the working modes of different motors, has more optimized functions, more flexible applications and more stable performance.

[0004] The technical solution adopted by the utility model to achieve the above-mentioned purpose is:

[0005] A three-level high-voltage combined inverter comprises a charging part, a rectifying part, a capacitor part, an inverter part, and an output part; the charging part is connected to the rectifying part through an input inductor, and two identical energy storage output circuits connected in parallel are connected in series after the rectifying part, and each energy storage output circuit comprises a capacitor part, an inverter part, and an output part, the capacitor part comprises an energy storage filter capacitor, the inverter part comprises an inverter module IGBT and a drive control circuit, the output part comprises an output inductor and an output contactor, and the output part is connected to a load.

[0006] The charging part comprises a charging resistor, a charging contactor and a main contactor. The charging resistor and the charging contactor are connected in series and then connected in parallel with the main contactor.

[0007] The charging contactor, main contactor and output contactor are all high-voltage AC vacuum contactors.

[0008] The rectifying part is composed of six rectifying diode modules.

[0009] The energy storage filter capacitor adopts a high-voltage film capacitor.

[0010] The input reactor and the output reactor adopt iron core reactors with enhanced filtering performance, so as to reduce the high-order harmonics outputted to the motor by the inverter part during switching.

[0011] The inverter module IGBT comprises a high-power IGBT module and a diode. Each phase has four IGBTs and a clamping diode to form a three-level topology structure.

[0012] The drive control circuit includes a fiber optic control board, a sampling board, a main board, a photoelectric conversion board, and a drive power supply board. The power supply of the drive control circuit is provided by a switching power supply. The main board and the sampling board are respectively connected to the fiber optic control board, and the fiber optic control board is connected to the photoelectric conversion board through optical fiber communication. The photoelectric conversion board is directly connected to the control electrode G, the collector C, and the emitter E of the high-power IGBT module to control the opening and closing of the IGBT. The drive power of the photoelectric conversion board is provided by the drive power supply board. Each IGBT corresponds to a photoelectric conversion board and a drive power supply board. The sampling board mainly collects the rectified bus voltage, connects the three potentials of P, O, and N, and transmits the signal to the fiber optic control board and then to the main board. The fiber optic control boards all adopt photoelectric isolation conversion mode to convert electrical signals into optical fiber signals connected to the photoelectric conversion board, which effectively ensures the stability of signal transmission and has strong anti-interference ability.

[0013] The main board of the drive control loop is also provided with a 485 communication interface to connect with the PLC and the human-machine interface screen, and a communication board is added at the same time, which has a CAN communication function to realize synchronous control.

[0014] The power supply of the driving control circuit adopts a high-power switching power supply, which is converted into 24V to power the control board, wherein the photoelectric conversion board is driven by the driving power board to convert the 24V power supply into -10V, 15V, 26V, etc. to drive the photoelectric conversion board.

[0015] The external wiring of the three-level high-voltage combination inverter uses explosion-proof quick-plug cable connectors; the circuit components of the inverter part are all installed on the backplane; the busbars inside the inverter use DC laminated busbars.

[0016] The beneficial effects of the utility model are:

[0017] The three-level high-voltage combination inverter adopts a three-level hardware topology structure, and each phase can output three levels, so that the line (phase) voltage has more step waves to simulate the sine wave, which reduces the output waveform distortion and makes the vector control more precise. It can be used to control AC asynchronous induction motors and permanent magnet synchronous motors, and can meet the working modes of different motors.

[0018] The three-level high-voltage combination inverter adopts a modular design. On the premise of meeting general needs, it can be configured with different communication expansion cards and integrated expansion cards to flexibly meet personalized and industry customization to meet various complex and high-performance transmission requirements.

[0019] The stability of three-level high-voltage combination inverters used in underground coal mines has been significantly improved, the failure rate has been greatly reduced, the size of the equipment has been greatly reduced, the cost has been reduced, and it is also convenient to transport. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a circuit connection block diagram of the utility model;

[0021] Figure 2 It is the overall circuit principle diagram of the utility model.

[0022] In the figure, 1 is the charging resistor; 2 is the charging contactor; 3 is the input inductor; 4 is the main contactor; 5 is the rectifier part; 6 is the energy storage filter capacitor; 7 is the drive control circuit; 8 is the inverter part; 9 is the output inductor; 10 is the output contactor; 11 is the load. DETAILED DESCRIPTION

[0023] The utility model is further described below in conjunction with the accompanying drawings.

[0024] A three-level high-voltage combined inverter, such as Figure 1 The invention comprises a charging part, a rectifying part, a capacitor part, an inverter part, and an output part; the charging part is connected to the rectifying part through an input inductor, and two identical energy storage output circuits connected in parallel with each other are connected in series after the rectifying part, and each energy storage output circuit comprises a capacitor part, an inverter part, and an output part, the capacitor part comprises an energy storage filter capacitor, the inverter part is connected with a drive control circuit, the output part comprises an output inductor and an output contactor, and the output part is connected to a load.

[0025] The charging part includes a charging resistor, a charging contactor and a main contactor. The charging resistor and the charging contactor are connected in series and then connected in parallel with the main contactor.

[0026] The drive control circuit includes a fiber optic control board, a sampling board, a main board, a photoelectric conversion board, and a drive power board. The 24V power supply of the drive control circuit is provided by a switching power supply. The main board and the sampling board are respectively connected to the fiber optic control board, which is connected to the photoelectric conversion board of the inverter module IGBT through optical fiber communication. The photoelectric conversion board is directly connected to the three pins of the IGBT (control electrode G, collector electrode C, and emitter electrode E) to control the opening and closing of the IGBT. The drive power supply of the photoelectric conversion board is provided by the drive power board. Each IGBT corresponds to a photoelectric conversion board and a drive power board. The sampling board mainly collects the rectified bus voltage, connects the three potentials of P, O, and N, and transmits the signal to the fiber optic control board and then to the main board.

[0027] The specific embodiment circuit connection is as follows Figure 2As shown, the charging contactor, main contactor and output contactor all use high-voltage AC vacuum contactors; the rectifier part is composed of 6 rectifier diode modules; the energy storage filter capacitor uses high-voltage film capacitors; the input reactor and output reactor use iron core reactors with enhanced filtering performance to reduce the high-order harmonics output to the motor when the inverter is switched; the inverter part uses imported high-power IGBT modules and diodes, and each phase has four IGBTs and a clamping diode to form a three-level topology; the main board of the drive control circuit has a 485 communication interface to connect with the PLC and the human-machine interface screen, and a communication board is added with CAN communication function to achieve synchronous control. The optical fiber control board all adopts the photoelectric isolation conversion method to convert the electrical signal into the optical fiber signal and connect it to the photoelectric conversion board, which can effectively ensure the stability of signal transmission and has strong anti-interference ability; the sampling board adopts the series resistance step-down method to convert the bus voltage into a low voltage signal and transmit it to the optical fiber control board; the photoelectric conversion board adopts the photoelectric isolation conversion method to convert the optical fiber signal into an electrical signal to drive the IGBT to open and close.

[0028] The connection method between each control board is as follows: the sampling board converts the high voltage signal into a low voltage signal to the fiber optic control board, the fiber optic control board transmits all collected signals (voltage, current, temperature, etc.) to the main board, and the main board transmits the driving electrical signal to the fiber optic control board according to the data, and then converts it into an optical signal, which is transmitted to the photoelectric conversion board by optical fiber and then drives the inverter module.

[0029] The control circuit power supply adopts a high-power switching power supply, which is converted into 24V to power the control board. The photoelectric conversion board is driven by the power supply board to convert the 24V power supply into -10V, 15V, 26V, etc. to drive the photoelectric conversion board.

[0030] The external wiring of the three-level high-voltage combination inverter uses explosion-proof quick-plug cable connectors, which makes it easy and quick to connect the power cable. The high-power IGBT modules and diodes in the inverter part are all imported ABB brands, all of which are installed on the back panel. You only need to remove the connecting screws between the capacitor busbar and the IGBT busbar and open the door from the back to replace and inspect. The design of the inverter part of the three-level high-voltage combination inverter is modular, and the heat dissipation of each module should be concentrated on the water cooling plate. The overall assembly is simple and convenient, and it is easy to replace a single faulty component.

[0031] The busbar inside the three-level high-voltage combination inverter adopts a DC laminated busbar, which reduces stray inductance and reduces the IGBT module shutdown spike. The compact design reduces the size of the whole machine, is easy to install and replace, durable, highly reliable and safe.

[0032] The energy storage filter capacitor uses high-performance high-voltage film capacitors with a lifespan of up to 100,000 hours, high voltage resistance, and extremely high insulation resistance. It has low ESR (equivalent series resistance), strong ripple current resistance, strong pulse resistance, high reliability, extremely low loss, low heat generation, and long service life.

[0033] All driving signals adopt photoelectric isolation conversion mode, which can effectively ensure the stability of signal transmission and have strong anti-interference ability.

[0034] The mainboard is equipped with a 485 communication interface to connect with the PLC and the human-machine interface screen. There is also a Chinese LCD display inside the inverter, which can display the inverter's operating status, DC voltage, power device temperature, output current, power and fault information in real time, as well as the inverter's key point temperature and fault information and other parameters. It also has a CAN communication function module to achieve synchronous control.

[0035] The three-level high-voltage combined inverter adopts DC-AC-DC frequency conversion control technology, has multiple control modes, a wide speed regulation range, flexible and convenient speed regulation, strong anti-interference ability and long service life; it adopts a three-level hardware topology structure, adopts the current domestic leading vector control technology, high-performance speed control, torque control, simple PLC control program, flexible input and output terminals, multiple mainstream communication settings, etc., to meet the requirements of various complex and high-performance transmissions, and is the best choice for underground frequency conversion and speed regulation devices.

Claims

1. A three-level high-voltage combined inverter, characterized in that: It includes a charging part, a rectifying part, a capacitor part, an inverter part, and an output part; the charging part is connected to the rectifying part through an input inductor, and two identical energy storage output circuits connected in parallel are connected in series after the rectifying part. Each energy storage output circuit includes a capacitor part, an inverter part, and an output part. The capacitor part includes an energy storage filter capacitor, the inverter part includes an inverter module IGBT and a drive control circuit, the output part includes an output inductor and an output contactor, and the output part is connected to the load.

2. A three-level high-voltage combined inverter according to claim 1, characterized in that: The charging part comprises a charging resistor, a charging contactor and a main contactor. The charging resistor and the charging contactor are connected in series and then connected in parallel with the main contactor.

3. A three-level high-voltage combined inverter according to claim 2, characterized in that: The charging contactor, main contactor and output contactor are all high-voltage AC vacuum contactors.

4. A three-level high-voltage combined inverter according to claim 1, characterized in that: The rectifying part is composed of six rectifying diode modules.

5. The three-level high-voltage combined inverter according to claim 1, characterized in that: The energy storage filter capacitor adopts a high-voltage film capacitor.

6. A three-level high-voltage combined inverter according to claim 1, characterized in that: The input reactor and the output reactor adopt iron core reactors with enhanced filtering performance.

7. A three-level high-voltage combined inverter according to claim 1, characterized in that: The inverter module IGBT comprises a high-power IGBT module and a diode. Each phase has four IGBT modules and a clamping diode to form a three-level topology structure.

8. The three-level high-voltage combined inverter according to claim 1, characterized in that: The drive control circuit includes a fiber optic control board, a sampling board, a main board, a photoelectric conversion board, and a drive power supply board; the fiber optic control board adopts a photoelectric isolation conversion method to convert electrical signals into fiber optic signals connected to the photoelectric conversion board, the main board and the sampling board are respectively connected to the fiber optic control board, the fiber optic control board is connected to the photoelectric conversion board through optical fiber communication, the photoelectric conversion board is directly connected to the control electrode G, the collector electrode C, and the emitter electrode E of the high-power IGBT module to control the opening and closing of the IGBT; the power supply of the drive control circuit is provided by a switching power supply; the drive power supply of the photoelectric conversion board is provided by the drive power supply board, each IGBT corresponds to a photoelectric conversion board and a drive power supply board, the sampling board collects the rectified bus voltage, connects the three potentials of P, O, and N, and transmits the signal to the fiber optic control board and then to the main board; the main board of the drive control circuit is also provided with a 485 communication interface and a communication board.

9. A three-level high-voltage combined inverter according to claim 8, characterized in that: The power supply of the driving control circuit adopts a high-power switching power supply, which is converted into 24V to power the control board, wherein the photoelectric conversion board is driven by the driving power board to convert the 24V power supply into -10V, 15V, 26V to drive the photoelectric conversion board.

10. The three-level high-voltage combined inverter according to claim 1, characterized in that: The external wiring of the three-level high-voltage combination inverter uses explosion-proof quick-plug cable connectors; the circuit components of the inverter part are all installed on the backplane; the busbars inside the three-level high-voltage combination inverter use DC laminated busbars.

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