Special high-performance four-quadrant frequency converter for electromagnetic industry

Abstract

The utility model discloses a special high-performance four-quadrant frequency converter for the electromagnetic industry, which belongs to the technical field of power electronics, and comprises a main topology part and a control part, the main topology part comprises an input filtering part, a rectification filtering part and an inversion part, the input filtering part comprises a network side inductor L1, a filtering capacitor C1 and a machine side inductor L2, and the rectification filtering part comprises a three-phase half-bridge insulated gate bipolar transistor module, a first bus capacitor Cd1, a second bus capacitor Cd2, a first voltage-sharing resistor Rd1, a second voltage-sharing resistor Rd2 and a buffer loop. The inversion part comprises one or three paths of three-phase half-bridge insulated gate bipolar transistor modules, and the control part comprises a power supply board, a detection board, a rectification side main control board, an inversion side main control board, a rectification side driving board, an inversion side driving board and a driving board.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and more specifically, to a high-performance four-quadrant frequency converter for the electromagnetic industry. Background Technology

[0002] In today's rapidly growing economy, the treatment of steel from certain industrial waste and raw materials has become a crucial step. For example, in the coal industry, iron impurities such as detonators and nails mixed in with coal not only affect safe production but also the quality of the coal. In the ceramics industry, raw materials such as limestone and silica contain varying amounts of iron and iron compounds. The presence of iron causes brown or black spots on the surface of ceramics, affecting the whiteness of the product and lowering its grade. Directly landfilling or incinerating scrap metal not only wastes resources but also pollutes the environment. Therefore, recycling these iron products is of paramount importance.

[0003] Traditional recycling methods are mostly manual, which is time-consuming, labor-intensive, and inefficient. Electromagnetic separators can effectively improve efficiency. Their working principle is based on the principle of electromagnets. Electromagnets generate a strong magnetic field when energized, using this field to attract and separate ferromagnetic impurities from materials. When material passes under the separator, if it contains ferromagnetic impurities, these impurities will be attracted to the electromagnet under the influence of the magnetic field. This is because ferromagnetic materials are magnetized in a magnetic field and thus attracted by the electromagnet's magnetic force. Electromagnetic separators typically consist of an excitation system, a conveyor belt, and control equipment. As material passes under the separator, ferromagnetic impurities are continuously attracted, achieving the purpose of iron removal. Traditionally, electromagnetic separators are powered using PLC control technology, directly connecting the electromagnet to the power grid, or through non-isolated DC-DC converters. These methods suffer from drawbacks such as high energy consumption, large current surges in the power grid, and significant harmonic pollution, making on-site protection difficult and posing challenges to heat dissipation in the electromagnetic separator.

[0004] To address the aforementioned problems, a technical solution is provided. Utility Model Content

[0005] The purpose of this invention is to provide a high-performance four-quadrant frequency converter specifically for the electromagnetic industry, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a high-performance four-quadrant frequency converter specifically for the electromagnetic industry, mainly composed of a main topology and a control section. The main topology includes an input filtering section, a rectifier filtering section, and an inverter section. The input filtering section adopts a passive LCL filter form, which includes a grid-side inductor L1, a filter capacitor C1, and a machine-side inductor L2. The capacitive inductance value of the input filtering section comprehensively considers the grid-side frequency, the machine-side switching frequency, and the capacitive resonant frequency to achieve effective filtering of the input current and reduce harmonic current flowing into the grid. The rectifier filtering section includes a three-phase half-bridge insulated-gate bipolar transistor module and a first bus capacitor C1. d 1. Second bus capacitor C d 2. First equalizing resistor R d 1. Second equalizing resistor R d 2 and buffer circuit, the first bus capacitor C d 1. The second bus capacitor C d 2. Parallel connection of the first voltage equalizing resistor R d 1. The second voltage equalizing resistor R d 2. For stabilizing the bus voltage, the buffer circuit includes a buffer resistor R1 to protect the three-phase half-bridge insulated gate bipolar transistor module from excessive voltage surges during switching; the inverter section includes one or three three-phase half-bridge insulated gate bipolar transistor modules.

[0007] The control section includes a power supply board, a detection board, a rectifier-side main control board, an inverter-side main control board, a rectifier-side drive board, an inverter-side drive board, and a drive board. The power supply board is controlled by the rectifier-side fan and relay control signals, and also provides energy to the 24V variable-speed fan and the primary side of the relay, ensuring normal power supply to each sub-circuit. The detection board includes input R, S, T detection circuits and grid-side input current detection circuits, acquiring input voltage and current signals in real time. The rectifier-side main control board is responsible for calculation and control, receiving signals from the detection board and the rectifier-side drive board, and outputting rectifier-side drive signals. The inverter-side main control board performs calculation and control, receiving signals from the inverter-side drive board, outputting inverter-side drive signals, and controlling the three-phase half-bridge insulated-gate bipolar transistors in the inverter section. The transistor module converts DC power to AC power output. The rectifier-side main control board and the inverter-side main control board are connected by a ribbon cable to transmit terminal start signals and comprehensive fault signals. The rectifier-side drive board mainly consists of a multi-winding flyback switching power supply circuit, a machine-side input current detection circuit, a drive circuit, a temperature measurement circuit, and a bus detection circuit. It converts the control signals from the main control board into the signals required to drive the three-phase half-bridge insulated-gate bipolar transistor module and monitors and protects the operating status of the three-phase half-bridge insulated-gate bipolar transistor module. The inverter-side drive board mainly consists of a multi-winding flyback switching power supply circuit, an output current detection circuit, a drive circuit, a temperature measurement circuit, and a bus detection circuit, and works in conjunction with the inverter-side main control board.

[0008] Using the above scheme, users can set the bus voltage according to their needs before normal startup. If no setting is made, the default bus voltage will be used. In this case, there are two ways to start the frequency converter.

[0009] In a preferred embodiment, during the first startup, the AFE rectifier is first started using the rectifier-side keypad. When the four-quadrant inverter starts, the detection board acquires the three-phase input voltage signals to obtain the phase relationship of the three-phase voltages. The detection board sends the preliminary phase relationship and input current to the rectifier-side main control board. The main control board's logic processing circuit performs logic synthesis on the three-phase input voltage phase signals to obtain the drive signal input to the three-phase half-bridge insulated-gate bipolar transistor module. The drive control circuit performs redundancy processing on the drive signal output from the logic processing circuit and then outputs it to the drive circuit input to the three-phase half-bridge insulated-gate bipolar transistor module, turning on the rectifier circuit. After passing through the buffer circuit, a certain voltage relay is activated, and the bus reaches the set point. Then, the inverter-side circuit is started by setting the frequency using the keypad, allowing normal output.

[0010] As a preferred implementation, in the second startup, the user first sets the bus voltage according to the requirements and starts the inverter using the inverter-side keypad. The inverter-side main control board is interconnected with the rectifier-side main control board in digital form. The inverter starts the rectifier first and then the inverter to complete the startup.

[0011] Using the above solution, if faults such as overcurrent, overtemperature, or input phase-locked loop failure occur during operation, the display interface will show the corresponding code and the system will shut down. It is worth noting that when multiple outputs are connected in parallel, if one output fails, a fault code will be displayed, but the system will not shut down. Users need to perform maintenance within a reasonable timeframe.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] This high-performance four-quadrant frequency converter, specifically designed for the electromagnetic industry, reduces power consumption by employing a four-quadrant frequency converter. By adopting AFE rectification technology, it can effectively reduce harmonic currents on the grid side, thereby reducing harmonic pollution to the grid.

[0014] This high-performance four-quadrant frequency converter, specifically designed for the electromagnetic industry, features multiple protection functions, such as over-temperature, over-voltage, and over-current protection, thereby improving the overall reliability of the system. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the topology of the single-channel output main circuit of this utility model.

[0016] Figure 2 This is a schematic diagram of the structure of the multi-output control section of this utility model.

[0017] Figure 3 This is a schematic diagram illustrating the basic principle of an electromagnetic separator. Detailed Implementation Example

[0018] Please see Figure 1 This utility model provides a single-output main circuit topology for a high-performance four-quadrant frequency converter specifically for the electromagnetic industry. The main topology includes an input filter section, a rectifier filter section, and an inverter section. The input filter section adopts a passive LCL filter form, which includes a grid-side inductor L1, a filter capacitor C1, and a machine-side inductor L2. The capacitance value of the input filter section comprehensively considers the grid-side frequency. and machine-side switching frequency and capacitive resonant frequency The network-side frequency and machine-side switching frequency satisfy To achieve effective filtering of the input current and reduce harmonic current flowing into the power grid, the rectifier and filter section includes a three-phase half-bridge insulated-gate bipolar transistor module and a first bus capacitor C. d 1. Second bus capacitor C d 2. First equalizing resistor R d 1. Second equalizing resistor R d 2 and buffer circuit, the first bus capacitor Cd 1. The second bus capacitor C d 2. Parallel connection of the first voltage equalizing resistor R d 1. The second voltage equalizing resistor R d 2. For stabilizing the bus voltage, the buffer circuit includes a buffer resistor R1 to protect the three-phase half-bridge insulated-gate bipolar transistor module from excessive voltage surges during switching. The filtering section considers the bus overvoltage point of 800V and the overcurrent point of 112A, leaving a certain margin, and selects a 1200V, 150A three-phase half-bridge insulated-gate bipolar transistor module. The buffer resistor R1 is selected as 20Ω, 80W. The first bus capacitor C... d 1 and the second bus capacitor C d 2. Select a configuration of two series and two parallel capacitors of 400V 8200uF, with each bus capacitor connected in parallel to the first voltage equalizing resistor R of 51kΩ / 5W. d 1 and the second equalizing resistor R d 2. The inverter side selects a 1200V 300A three-phase half-bridge insulated gate bipolar transistor module (Q7Q10). The inverter section includes one or three three-phase half-bridge insulated gate bipolar transistor modules. Example

[0019] Please see Figure 2This utility model provides a multi-output control section for a high-performance four-quadrant frequency converter specifically for the electromagnetic industry. The inverter side uses three three-phase half-bridge insulated-gate bipolar transistor modules (Q7Q10, Q8Q11, Q9Q12) in parallel configuration for the three outputs. The multiple outputs are connected in parallel through a current-sharing reactor L3. The control section includes a power supply board, a detection board, a rectifier-side main control board, an inverter-side main control board, a rectifier-side drive board, an inverter-side drive board, and a drive board. The power supply board is controlled by the rectifier-side fan and relay control signals, and also provides energy to the 24V variable-speed fan and the primary side of the relay, ensuring normal power supply to each component circuit. The detection board includes input R, S, T detection circuits and a grid-side input current detection circuit, acquiring input voltage and current signals in real time. The rectifier-side main control board is responsible for calculation and control, receiving signals from the detection board and the rectifier-side drive board, and outputting rectifier-side drive signals. The inverter... The main control board on the rectifier side performs calculation and control functions, receives signals from the inverter-side drive board, outputs inverter-side drive signals, and controls the operation of the three-phase half-bridge insulated-gate bipolar transistor (IGBT) modules in the inverter section to convert DC power to AC power output. The rectifier-side main control board and the inverter-side main control board are connected by a ribbon cable to transmit terminal start signals and comprehensive fault signals. The rectifier-side drive board mainly consists of a multi-winding flyback switching power supply circuit, a machine-side input current detection circuit, a drive circuit, a temperature measurement circuit, and a bus detection circuit. It converts the control signals from the main control board into the signals required to drive the three-phase half-bridge IGBT modules and monitors and protects the operating status of the three-phase half-bridge IGBT modules. The inverter-side drive board mainly consists of a multi-winding flyback switching power supply circuit, an output current detection circuit, a drive circuit, a temperature measurement circuit, and a bus detection circuit, and works in conjunction with the inverter-side main control board. Example

[0020] This utility model provides a starting method for a high-performance four-quadrant frequency converter specifically for the electromagnetic industry. Before normal startup, the user can set the bus voltage (450V-700V) according to the requirements. If no setting is made, the default bus voltage is 550V. At this time, there are two ways to start the frequency converter.

[0021] In the first startup, the AFE rectifier is started using the rectifier-side keypad. When the four-quadrant inverter starts, the detection board acquires the three-phase input voltage signals to obtain the phase relationship of the three-phase voltages. The detection board sends the preliminary phase relationship and input current to the rectifier-side main control board. The main control board's logic processing circuit performs logic synthesis on the three-phase input voltage phase signals to obtain the drive signal input to the three-phase half-bridge insulated-gate bipolar transistor module. The drive control circuit performs redundancy processing on the drive signal output from the logic processing circuit and then outputs it to the drive circuit input to the three-phase half-bridge insulated-gate bipolar transistor module, turning on the rectifier circuit. After passing through the buffer circuit, a certain voltage relay is activated, and the bus reaches the set point. Then, the inverter-side circuit is started by setting the frequency using the keypad, allowing normal output.

[0022] In the second startup method, the user first sets the bus voltage according to requirements, then starts the inverter using the inverter-side keypad. The digital output terminal (DO) of the inverter-side main control board is connected to the digital input terminal (DI) of the rectifier-side main control board. The rectifier starts first, then the inverter starts, and the frequency converter outputs normally.

[0023] During normal output, such as Figure 3 When the material passes through the belt conveyor, at time t1, the material reaches the bottom of the electromagnetic separator. If the material contains ferromagnetic impurities, at time t2, the iron will be attracted to the electromagnet under the influence of the magnetic field. Then, at time t3, the iron and other impurities are separated and processed.

[0024] During operation, if faults such as overcurrent, overtemperature, or input phase-locked loop failure occur, the display interface will show the corresponding code and the machine will stop. Users can refer to the manual to highlight the fault type based on the code and make corresponding judgments. In a multi-output four-quadrant frequency converter, when one of the channels experiences an open circuit fault, and the branch current sensor is found to have no output during operation, the frequency converter will display a certain fault code, but will not stop outputting and can be used at a reduced rating.

Claims

1. A high performance four quadrant frequency converter dedicated to the electromagnetic industry, consisting of a main topology part and a control part, characterized in that, The main topology includes an input filtering section, a rectification filtering section, and an inverter section. The control section includes a power supply board, a detection board, a rectifier-side main control board, an inverter-side main control board, a rectifier-side driver board, and an inverter-side driver board. The power supply board, the detection board, and the rectifier-side driver board are all connected to the rectifier-side main control board. The rectifier-side main control board is connected to the inverter-side main control board. The inverter-side main control board is connected to the inverter-side driver board.

2. A high performance four quadrant frequency inverter for electromagnetic industry as claimed in claim 1 wherein , the input filter part adopts passive LCL filter form, which includes grid side inductance L1, filter capacitor C1 and machine side inductance L2, the rectifier filter part includes three-phase half-bridge insulated gate bipolar transistor module, first bus capacitor C d 1、second bus capacitor C d 2、first voltage-sharing resistor R d 1、second voltage-sharing resistor R d 2 and buffer circuit, the first bus capacitor C d 1、the second bus capacitor C d 2 is connected in parallel with the first voltage-sharing resistor R d 1、the second voltage-sharing resistor R d 2, the buffer circuit contains buffer resistor R1, which protects the three-phase half-bridge insulated gate bipolar transistor module from high voltage impact during switching process, and the inverter part includes 1-way or 3-way three-phase half-bridge insulated gate bipolar transistor module.

3. A high performance four quadrant frequency inverter for electromagnetic industry as claimed in claim 1 wherein The power supply board is controlled by the rectifier-side fan and relay control signals. The detection board includes input R, S, T detection circuits and grid-side input current detection circuits to collect input voltage and current signals in real time. The rectifier-side main control board is responsible for calculation and control, receiving signals from the detection board and the rectifier-side drive board, and outputting rectifier-side drive signals. The inverter-side main control board receives signals from the inverter-side drive board and outputs inverter-side drive signals to control the operation of the three-phase half-bridge insulated gate bipolar transistor module in the inverter section, realizing the conversion of DC power to AC power output. The rectifier-side main control board and the inverter-side main control board are connected by ribbon cables to transmit terminal start signals and comprehensive fault signals.

4. The high performance four quadrant frequency inverter for electromagnetic industry as claimed in claim 1 wherein, The rectifier-side drive board mainly consists of a multi-winding flyback switching power supply circuit, a machine-side input current detection circuit, a drive circuit, a temperature measurement circuit, and a bus detection circuit. It converts the control signals from the main control board into the signals required to drive the three-phase half-bridge insulated-gate bipolar transistor module and monitors and protects the operating status of the three-phase half-bridge insulated-gate bipolar transistor module. The inverter-side drive board mainly consists of a multi-winding flyback switching power supply circuit, an output current detection circuit, a drive circuit, a temperature measurement circuit, and a bus detection circuit, and works in conjunction with the inverter-side main control board.

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