A mine frequency converter control system and control method based on RC-IGBT

Abstract

The present invention discloses a mine frequency converter control system based on RC-IGBT and a control method thereof, belonging to the technical field of mine frequency converter control systems based on RC-IGBT; the technical problem to be solved is: to provide an improvement on the hardware structure of a mine frequency converter control system based on RC-IGBT; the technical scheme adopted to solve the above technical problem is: comprising a plurality of main circuits and a control unit connected to each other, the main circuit comprising a power supply network, the output end of the power supply network being sequentially connected to a network-side filtering unit, a network-side RC-IGBT three-level rectifying unit, a DC bus support capacitor, a machine-side RC-IGBT three-level inverter unit, an AC measuring filter inductor and then connected to an AC synchronous motor; the control unit comprises a main control unit, a control signal acquisition unit and a control signal sending unit, the signal input end of the main control unit is connected to the control signal acquisition unit through a wire, and the main control unit is connected to the control signal sending unit through a VME bus; the present invention is applied to mine frequency converters.

Description

Technical Field

[0001] The invention discloses a mine frequency converter control system based on RC-IGBT and a control method thereof, belonging to the technical field of mine frequency converter control systems based on RC-IGBT and a control method thereof. Background Art

[0002] The high degree of electrification and intelligence of power equipment is the only way for the coal industry to move towards industrial automation 4.0 and even unmanned operation. The frequency converter is one of the core supporting equipment. The operation of coal mine mechanical power equipment has put forward strict requirements on motor transmission, intrinsic safety explosion protection, signal interference control, etc. The dedicated control platform for mine frequency converter is the guarantee of energy conservation and safe production in mines. High-power mine frequency converter equipment with a power of more than 3000kW generally adopts AC synchronous motor control. There are two forms of electronic control systems: synchronous motor circuit based on thyristor AC-AC frequency conversion transmission, and AC-DC-AC frequency conversion circuit based on IGBT technology.

[0003] Due to the unique advantages of reverse-conducting IGBT in power density, good safe working area, loss characteristics and small junction temperature fluctuation, high-power reverse-conducting IGBT modules are applied to the special platform of mining inverters to reduce the size of the inverter, improve the system power density, and optimize the thermal characteristics of the system to improve stability. The current four-quadrant converter usually uses IGBT modules with IGBT reverse parallel freewheeling diodes. Under the same package, reverse-conducting IGBT has more advantages than traditional IGBT modules, but the existing mining inverters have poor current tolerance, heat dissipation and temperature rise characteristics. Therefore, it is necessary to propose a mining inverter control system based on RC-IGBT and a control method thereof. Summary of the invention

[0004] In order to overcome the deficiencies in the prior art, the present invention aims to solve the technical problem of providing an improvement in the hardware structure of a mine frequency converter control system based on RC-IGBT.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a mine inverter control system based on RC-IGBT, including multiple main circuits and control units connected to each other, the main circuit including a power supply network, the output end of the power supply network is connected in series with the grid-side filter unit and then connected to the AC side of the grid-side RC-IGBT three-level rectifier unit, the DC side of the grid-side RC-IGBT three-level rectifier unit is connected in series with the DC bus support capacitor through a wire and then connected to the DC side of the machine-side RC-IGBT three-level inverter unit, the AC side of the machine-side RC-IGBT three-level inverter unit is connected in series with the AC filter inductor and then connected to the AC synchronous motor;

[0006] The control unit includes a main control unit, a control signal acquisition unit, and a control signal sending unit. The signal input end of the main control unit is connected to the control signal acquisition unit through a wire. The main control unit is connected to the control signal sending unit through a VME bus, and a pulse trigger signal is sent to the optical fiber trigger board of the control signal sending unit. The optical fiber trigger board is connected to the RC-IGBT power devices of the grid-side RC-IGBT three-level rectifier unit and the machine-side RC-IGBT three-level inverter unit through optical fibers.

[0007] The main control unit outputs a desaturation control PWM pulse to drive each RC-IGBT power device in the switch unit to turn on and off.

[0008] The main control unit is also connected to the monitoring system, Ethernet control module, mining inverter dedicated platform and encoder through wires;

[0009] The main control unit realizes data transmission with the monitoring system through the Modbus communication protocol, and the monitoring system is provided with a human-machine interface;

[0010] The main control unit realizes data transmission with the Ethernet control module supporting network control through the SCI communication interface;

[0011] The main control unit is connected to a dedicated platform for a mine frequency converter via a CAN bus, and the dedicated platform for a mine frequency converter is provided with overvoltage, overcurrent and overtemperature protection.

[0012] The main control unit includes a main control architecture based on DSP and FPGA, specifically including a host DSP, a slave DSP, and a slave FPGA, wherein the host DSP and the slave DSP and the slave FPGA realize data transmission through an SPI communication interface;

[0013] The main control unit realizes full digital control of the dedicated platform for mining frequency converter based on RC-IGBT through the host DSP, slave DSP and slave FPGA, and transmits the control signal to the RC-IGBT power device through optical fiber through voltage and current digital closed-loop control and carrier phase shift modulation;

[0014] The host DSP and the slave DSP are provided with a control algorithm implementation unit inside. The sampling signal output by the control signal acquisition unit is input into the host DSP through A / D conversion for operation. The control algorithm implementation unit receives the sensor information after the sampling signal conditioning of the control signal acquisition unit, calculates the modulation signal according to the power given value, and then sends the pulse trigger signal to the optical fiber trigger board;

[0015] The slave FPGA is used to complete the overvoltage, overcurrent, overtemperature protection and reverse conduction IGBT drive pulse trigger control algorithm of the dedicated platform for mining inverters.

[0016] The control signal acquisition unit includes a voltage sensor, a current sensor, and a temperature sensor for collecting the operating temperature of the inverter, wherein the voltage sensor is used to detect three grid voltages, two DC side capacitor voltages, and three load voltages in real time, and the current sensor is used to detect three grid currents and three load currents in real time.

[0017] The grid-side RC-IGBT three-level rectifier unit and the machine-side RC-IGBT three-level inverter unit are both composed of three groups of neutral point clamped three-level power modules, and the neutral point clamped three-level power modules include: each phase bridge arm in the rectifier and inverter topology is composed of four RC-IGBT fully controlled devices with integrated freewheeling diodes and two clamping diodes, which are connected in parallel through high-voltage DC bus support capacitors and share a DC bus;

[0018] The two ends of the clamping diode are connected with a clamping resistor for ensuring that the output end of the power unit is reliably clamped to a zero level, and the selected clamping resistor is specifically a water-cooled resistor.

[0019] The host DSP specifically adopts a model of TMS320F28335, the slave DSP specifically adopts a model of TMS320F28069F, and the slave FPGA specifically adopts a model of Sparten-6 FPGA;

[0020] The voltage sensor is specifically of model AV 100-2000, the current sensor is specifically of model LF 505 S SP1324V, and the temperature sensor is specifically of model DS18B20;

[0021] The RC-IGBT in the neutral point clamped three-level power module adopts a model of 6500V / 1000A, and the clamping diode adopts a fast recovery diode of model D1331SH.

[0022] A mine frequency converter control method based on RC-IGBT comprises the following steps:

[0023] Step 1: In the IGBT mode, the host DSP triggers and cuts off the desaturation control of the freewheeling diode of the slave FPGA by judging the reverse conduction state and the load current zero point;

[0024] Step 2: Detect the freewheeling diode mode to prevent the RC-IGBT from turning on;

[0025] Step 3: Before turning off the freewheeling diode, reduce the effect of excessive stored charge of the freewheeling diode on dynamic loss by driving the gate to +15V, thereby reducing the saturation;

[0026] Step 4: During the desaturation time of the freewheeling diode, the freewheeling diode conduction mode with Vge=0V is set;

[0027] Step 5: In the freewheeling diode mode, the load current zero crossing is detected and the RC-IGBT is turned on to achieve a smooth current transition from the freewheeling diode to the IGBT of the same power device;

[0028] Step 6: Detect the zero-crossing point of the load current in the IGBT mode and turn off the RC-IGBT to reduce the dynamic loss of the freewheeling diode.

[0029] The specific judgment steps of the control method are as follows:

[0030] 1) By judging the state of the current input PWM pulse, when the PWM pulse is a rising edge, the interlock timer with the set time is started to judge the current operation mode of the RC-IGBT;

[0031] 2) Determination of the reverse conduction state of RC-IGBT; when Vce is at a low level, it is determined that the current state is a high-level freewheeling diode mode. At this time, the gate voltage is 0V, which alleviates the high carrier density and reduces the stored charge in the on state;

[0032] 3) Load current zero point judgment: In the freewheeling diode mode, the load current zero crossing is detected and the RC-IGBT is turned on to achieve a smooth current transition from the freewheeling diode to the IGBT of the same power device;

[0033] Detect the zero-crossing point of the load current in IGBT mode and turn off the RC-IGBT to reduce the dynamic loss of the freewheeling diode;

[0034] 4) When the current input PWM pulse state is judged to be a falling edge, RGD is the gate resistance in the IGBT state, and the desaturation timer is set. The gate voltage is +15V, and the gate voltage is -15V after the desaturation timer ends.

[0035] 5) Determination of the reverse conduction state of RC-IGBT; when Vce is at a high level, the current state is judged to be a high-level IGBT mode, and the gate voltage is +15V. When the state of the current input PWM pulse is judged to be a falling edge, the gate voltage is -15V, and a cycle ends.

[0036] When the PWM pulse is on the rising edge, the setting time of the interlock timer is 20us;

[0037] When the state of the current input PWM pulse is a falling edge, the setting time of the desaturation timer is 19us.

[0038] The beneficial effects of the present invention compared with the prior art are as follows: the mine frequency converter control system based on RC-IGBT provided by the present invention can be applied to coal machine power equipment, has modular and universal characteristics and can realize cascading of up to four platforms; the frequency converter main topology uses a three-level four-quadrant midpoint clamping circuit based on RC-IGBT, which has better current sharing capability, heat dissipation and temperature rise control than traditional IGBT frequency converters; thereby, the control system has the characteristics of compact structure, good safe working area and high power density; the present invention overcomes the direct connection of the upper and lower bridge arms in actual applications caused by the forced segmented delay triggering of pulses in traditional control methods by optimizing diode desaturation control, thereby improving the maximum output capacity of the RC-IGBT frequency converter, and is suitable for medium-voltage and large-capacity mine hoist frequency conversion control applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described below in conjunction with the accompanying drawings:

[0040] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0041] Figure 2 It is the main circuit topology diagram of the present invention;

[0042] Figure 3 This is a flow chart of RC-IGBT drive control of the present invention;

[0043] In the figure: 11 is a grid-side filter unit, 12 is a grid-side RC-IGBT three-level rectifier unit, 13 is a DC bus support capacitor, 14 is a machine-side RC-IGBT three-level inverter unit, 15 is an AC measurement filter inductor, 16 is an AC synchronous motor, 21 is a main control unit, 22 is a control signal acquisition unit, and 23 is a control signal sending unit. DETAILED DESCRIPTION

[0044] like Figures 1 to 3 As shown, the present invention is a mine frequency converter control system based on RC-IGBT, including multiple main circuits and control units connected to each other, wherein the main circuit includes a power supply network, wherein the output end of the power supply network is connected in series with a network-side filter unit 11 and then connected to the AC side of a network-side RC-IGBT three-level rectifier unit 12, wherein the DC side of the network-side RC-IGBT three-level rectifier unit 12 is connected in series with a DC bus support capacitor 13 through a wire and then connected to the DC side of a machine-side RC-IGBT three-level inverter unit 14, wherein the AC side of the machine-side RC-IGBT three-level inverter unit 14 is connected in series with an AC filter inductor 15 and then connected to an AC synchronous motor 16;

[0045] The control unit includes a main control unit 21, a control signal acquisition unit 22, and a control signal sending unit 23. The signal input end of the main control unit 21 is connected to the control signal acquisition unit 22 through a wire. The main control unit 21 is connected to the control signal sending unit 23 through a VME bus, and sends a pulse trigger signal to the optical fiber trigger board of the control signal sending unit 23. The optical fiber trigger board is connected to the RC-IGBT power devices of the grid-side RC-IGBT three-level rectifier unit 12 and the machine-side RC-IGBT three-level inverter unit 14 through optical fibers.

[0046] The main control unit 21 outputs a desaturation control PWM pulse to drive each RC-IGBT power device in the switch unit to turn on and off.

[0047] The main control unit 21 is also connected to the monitoring system, Ethernet control module, mining inverter dedicated platform, and encoder through wires;

[0048] The main control unit 21 realizes data transmission with the monitoring system through the Modbus communication protocol, and the monitoring system is provided with a human-machine interface;

[0049] The main control unit 21 realizes data transmission with the Ethernet control module supporting network control through the SCI communication interface;

[0050] The main control unit 21 is connected to a dedicated platform for a mine frequency converter via a CAN bus, and the dedicated platform for a mine frequency converter is provided with overvoltage, overcurrent and overtemperature protection.

[0051] The main control unit 21 includes a main control architecture based on DSP and FPGA, specifically including a host DSP, a slave DSP, and a slave FPGA, wherein the host DSP and the slave DSP and the slave FPGA realize data transmission through an SPI communication interface;

[0052] The main control unit 21 realizes full digital control of the dedicated platform for mining frequency converter based on RC-IGBT through the host DSP, slave DSP and slave FPGA, and transmits the control signal to the RC-IGBT power device through optical fiber through voltage and current digital closed-loop control and carrier phase shift modulation;

[0053] The host DSP and the slave DSP are provided with a control algorithm implementation unit inside. The sampling signal output by the control signal acquisition unit 22 is input into the host DSP through A / D conversion for operation. The control algorithm implementation unit receives the sensor information after the sampling signal conditioning of the control signal acquisition unit 22, calculates the modulation signal according to the power given value, and then sends the pulse trigger signal to the optical fiber trigger board;

[0054] The slave FPGA is used to complete the overvoltage, overcurrent, overtemperature protection and reverse conduction IGBT drive pulse trigger control algorithm of the dedicated platform for mining inverters.

[0055] The control signal acquisition unit 22 includes a voltage sensor, a current sensor, and a temperature sensor for collecting the operating temperature of the inverter, wherein the voltage sensor is used to detect three grid voltages, two DC side capacitor voltages, and three load voltages in real time, and the current sensor is used to detect three grid currents and three load currents in real time.

[0056] The grid-side RC-IGBT three-level rectifier unit 12 and the machine-side RC-IGBT three-level inverter unit 14 are both composed of three groups of neutral point clamped three-level power modules, and the neutral point clamped three-level power modules include: each phase bridge arm in the rectifier and inverter topology is composed of four RC-IGBT fully controlled devices with integrated freewheeling diodes and two clamping diodes, which are connected in parallel through high-voltage DC bus support capacitors and share a DC bus;

[0057] The two ends of the clamping diode are connected with a clamping resistor for ensuring that the output end of the power unit is reliably clamped to a zero level, and the selected clamping resistor is specifically a water-cooled resistor.

[0058] The host DSP specifically adopts a model of TMS320F28335, the slave DSP specifically adopts a model of TMS320F28069F, and the slave FPGA specifically adopts a model of Sparten-6 FPGA;

[0059] The voltage sensor is specifically of model AV 100-2000, the current sensor is specifically of model LF 505 S SP1324V, and the temperature sensor is specifically of model DS18B20;

[0060] The RC-IGBT in the neutral point clamped three-level power module adopts a model of 6500V / 1000A, and the clamping diode adopts a fast recovery diode of model D1331SH.

[0061] A mine frequency converter control method based on RC-IGBT comprises the following steps:

[0062] Step 1: In the IGBT mode, the host DSP triggers and cuts off the desaturation control of the freewheeling diode of the slave FPGA by judging the reverse conduction state and the load current zero point;

[0063] Step 2: Detect the freewheeling diode mode to prevent the RC-IGBT from turning on;

[0064] Step 3: Before turning off the freewheeling diode, reduce the effect of excessive stored charge of the freewheeling diode on dynamic loss by driving the gate to +15V, thereby reducing the saturation;

[0065] Step 4: During the desaturation time of the freewheeling diode, the freewheeling diode conduction mode with Vge=0V is set;

[0066] Step 5: In the freewheeling diode mode, the load current zero crossing is detected and the RC-IGBT is turned on to achieve a smooth current transition from the freewheeling diode to the IGBT of the same power device;

[0067] Step 6: Detect the zero-crossing point of the load current in the IGBT mode and turn off the RC-IGBT to reduce the dynamic loss of the freewheeling diode.

[0068] The specific judgment steps of the control method are as follows:

[0069] 1) By judging the state of the current input PWM pulse, when the PWM pulse is a rising edge, the interlock timer with the set time is started to judge the current operation mode of the RC-IGBT;

[0070] 2) Determination of the reverse conduction state of RC-IGBT; when Vce is at a low level, it is determined that the current state is a high-level freewheeling diode mode. At this time, the gate voltage is 0V, which alleviates the high carrier density and reduces the stored charge in the on state;

[0071] 3) Load current zero point judgment: In the freewheeling diode mode, the load current zero crossing is detected and the RC-IGBT is turned on to achieve a smooth current transition from the freewheeling diode to the IGBT of the same power device;

[0072] Detect the zero-crossing point of the load current in IGBT mode and turn off the RC-IGBT to reduce the dynamic loss of the freewheeling diode;

[0073] 4) When the current input PWM pulse state is judged to be a falling edge, RGD is the gate resistance in the IGBT state, and the desaturation timer is set. The gate voltage is +15V, and the gate voltage is -15V after the desaturation timer ends.

[0074] 5) Determination of the reverse conduction state of RC-IGBT; when Vce is at a high level, the current state is judged to be a high-level IGBT mode, and the gate voltage is +15V. When the state of the current input PWM pulse is judged to be a falling edge, the gate voltage is -15V, and a cycle ends.

[0075] When the PWM pulse is on the rising edge, the setting time of the interlock timer is 20us;

[0076] When the state of the current input PWM pulse is a falling edge, the setting time of the desaturation timer is 19us.

[0077] The RC-IGBT-based mine inverter control system provided by the present invention relates to a high-power frequency conversion circuit of a reverse conducting-insulated gate bipolar transistor (RC-IGBT), in particular, a four-quadrant three-level mine inverter control system based on RC-IGBT. It includes a main circuit and a control unit connected to each other, and the main circuit includes: a grid-side filter unit 11, a grid-side RC-IGBT three-level rectifier unit 12, a DC bus support capacitor 13, a machine-side RC-IGBT three-level inverter unit 14, and an AC filter inductor 15, which are sequentially connected between the power supply network and the AC synchronous motor. The control unit includes a main control unit 21 composed of a main control architecture based on DSP and FPGA, a control signal acquisition unit 22 including a voltage and current acquisition module and an inverter temperature acquisition module, a control signal sending unit 23 composed of an optical fiber trigger receiving circuit based on VME bus, a human-machine control interface, an Ethernet control module supporting network control, a special platform for mining inverters, overvoltage, overcurrent, overtemperature protection, and an optimized reverse conduction IGBT desaturation control pulse trigger control algorithm.

[0078] The grid-side RC-IGBT three-level rectifier unit 12 is connected back-to-back with the machine-side RC-IGBT three-level inverter unit 14. The optimized drive pulses of the machine-side RC-IGBT three-level inverter unit 14 and the grid-side RC-IGBT three-level rectifier unit 12 are connected to the control module through optical fiber. The control signal is transmitted by optical fiber to achieve high and low voltage isolation. The main control unit 21 collects the grid-side voltage and current, DC capacitor voltage, load AC side voltage and current in real time. The main control unit 21 outputs optimized desaturation control PWM pulses to drive the opening and closing of each RC-IGBT power device in the 24 switch units.

[0079] The grid-side RC-IGBT three-level rectifier unit 12 and the machine-side RC-IGBT three-level inverter unit 14 are both composed of three groups of neutral point clamped three-level power modules, and the neutral point clamped three-level power modules include: each phase bridge arm in the rectifier and inverter topology is composed of four RC-IGBT fully controlled devices with integrated freewheeling diodes and two clamping diodes, which are connected in parallel through the high-voltage DC bus support capacitor 13 and share the DC bus; the RC-IGBT in the neutral point clamped three-level power module has a specification of 6500V / 1000A, and the clamping diode is a fast recovery diode of model D1331SH. The clamping resistors connected at both ends of the clamping diodes ensure that the output end of the power unit is reliably clamped to zero level, and the selected resistors are all water-cooled resistors.

[0080] The DC busbar supporting capacitors 13 all use capacitors of model B25856, and the DC voltage of each high-frequency capacitor can reach 2500V.

[0081] The neutral point of the grid-side RC-IGBT three-level rectifier unit 12 is clamped by the midpoint of the three-level power module as an input terminal connected to the grid-side filter unit 11 , and the neutral point of the machine-side RC-IGBT three-level inverter unit 14 is clamped by the midpoint of the three-level power module as an output terminal connected to the AC synchronous motor 16 .

[0082] The control unit includes a main control unit 21 with a built-in control algorithm implementation unit, a control signal acquisition unit 22 and a control signal sending unit 23. The digital signal processor (DSP) and field programmable gate array (FPGA) chip realize the full digital control of the RC-IGBT-based mining inverter dedicated platform, adopts voltage and current digital closed loop and carrier phase shift modulation technology, and the control signal is transmitted by optical fiber, realizing high and low voltage isolation, thereby improving the stability and reliability of the mining inverter platform. The digital signal processor (DSP) adopts TMS320F28335 and TMS320F28069 chips; the field programmable gate array chip adopts XC6SLX9-3TQG144I chip.

[0083] The control signal acquisition unit 21 includes a voltage sensor and a current sensor. The voltage sensor is used to detect 3-way grid voltage, 2-way DC side capacitor voltage, and 3-way load voltage in real time; the current sensor is used to detect 3-way grid current and 3-way load current in real time. The voltage sensor uses a voltage sensor of model AV 100-2000; the current sensor uses a current sensor of model LF505 S SP13 (24V).

[0084] The control algorithm implementation unit is implemented by the digital signal processors of DSP TMS320F28335 and TMS320F28069F to implement algorithm control and the FPGA Sparten-6 programmable logic chip to send out optimized desaturation control pulses. The 14 sampling signals output by the control signal acquisition unit 21 are input into the digital signal processor (DSP) through A / D conversion for calculation. The control algorithm implementation unit DSP completes the top-level algorithm, and the FPGA completes the overvoltage, overcurrent, and overtemperature protection of the mining inverter special platform and the optimized reverse conduction IGBT drive pulse trigger control algorithm. After receiving the 14-channel sampling conditioning information, the control algorithm implementation unit calculates the modulation signal according to the power given value, and then sends the pulse trigger signal to the optical fiber trigger board.

[0085] The human-machine interface adopts the human-machine interaction interface model MT8103IE, which has the best and perfect power isolation protection and can be easily applied to the complex environment of the mine. The human-machine interface and the main control unit 21 realize data transmission through Modbus protocol communication, which is convenient for on-site operation.

[0086] The Ethernet control module integrates the TCP / IP protocol stack inside the embedded serial port to Ethernet module to realize the networking control of the dedicated platform for mining inverters. The module is used to realize data transmission between the serial port and Ethernet, which is convenient for the PC in the mine dispatch room to adjust the coal machinery equipment in real time, or for remote communication between multiple serial port devices.

[0087] The main control architecture based on DSP and FPGA is implemented by digital signal processors of model DSP TMS320F28335 and TMS320F28069F to realize algorithm control and programmable logic chip of model FPGA Sparten-6 to send optimized desaturation control pulses. DSP and FPGA communicate through SPI, DSP TMS320F28335 is the host, DSP TMS320F28069F is the slave, and FPGA Sparten-6 is the slave, which satisfies the mutual data transmission between the lower computers. The motor control algorithm is implemented in DSPTMS320F28069F, and its position-free function library is used to form redundancy with the encoder signal, ensuring the stability and reliability of the platform.

[0088] The driving control process of the control method of the present invention is as follows: Figure 3 As shown, the traditional control method overcomes the forced segmented delay triggering of the pulse, which causes the upper and lower bridge arms to pass directly in actual applications. The RC-IGBT drive control steps of the present invention are as follows:

[0089] (1) Detect the freewheeling diode mode to prevent the RC-IGBT from turning on;

[0090] (2) Before turning off the freewheeling diode, the gate is driven to +15V to reduce the impact of the excessive storage charge of the freewheeling diode on the dynamic loss and reduce the saturation;

[0091] (3) During the desaturation time of the freewheeling diode, the freewheeling diode conduction mode with Vge = 0 V;

[0092] (4) In the freewheeling diode mode, the load current zero crossing is detected and the RC-IGBT is turned on to achieve a smooth current transition from the freewheeling diode to the IGBT of the same power device;

[0093] (5) Detect the zero-crossing point of the load current in IGBT mode and turn off the RC-IGBT to reduce the dynamic loss of the freewheeling diode. Determine the state of the current input PWM pulse. If it is a rising edge, start a 20us interlock timer to determine the current operation mode of the RC-IGBT.

[0094] The digital circuit based on DSP and FPGA of the present invention enhances the system computing capability, improves the pulse width output accuracy, shortens the control response time, and improves the system safety and stability.

[0095] The RC-IGBT drive control of the present invention mainly includes the following steps:

[0096] (1) Determine the state of the current input PWM pulse. If it is a rising edge, start a 20us interlock timer to determine the current operating mode of the RC-IGBT;

[0097] (2) Determination of the reverse conduction state of the RC-IGBT: If Vce is low, the current state is determined to be a high-level freewheeling diode mode. The gate voltage is set to 0V to alleviate the high carrier density and reduce the stored charge in the on state.

[0098] (3) Load current zero point judgment: In the freewheeling diode mode, the load current zero crossing is detected and the RC-IGBT is turned on to achieve a smooth current transition from the freewheeling diode to the IGBT of the same power device; the load current zero crossing in the IGBT mode is detected and the RC-IGBT is turned off to reduce the dynamic loss of the freewheeling diode.

[0099] (4) When the current input PWM pulse state is judged to be a rising or falling edge, RGD is the gate resistance in the IGBT state, and a 19us desaturation timer is started. The gate voltage is +15V. After the desaturation timer ends, the gate voltage is -15V. RGI is the gate diode resistance.

[0100] (5) Determination of the reverse conduction state of the RC-IGBT; if Vce is at a high level, the current state is determined to be a high-level IGBT mode, and the gate voltage is set to +15V to ensure that the power device is in the on state. When the current input PWM pulse state is determined to be a falling edge, the gate voltage is set to -15V, and one cycle ends.

[0101] The driving control method of the IBGT of the anti-parallel freewheeling diode adopted in the present invention only needs to apply a driving signal to the IGBT gate. For the RC-IGBT operating in the freewheeling diode mode, although the gate high-level pulse achieves a smaller dynamic loss, it will increase the reverse conduction loss of the module. This characteristic has a great impact on the operation of coal machinery equipment. The increase in conduction loss leads to a decrease in the efficiency of the dedicated platform for mining inverters and a deterioration in the thermal characteristics of the system.

[0102] The present invention is based on the characteristics of the RC-IGBT chip integrated freewheeling diode. When it is judged that the power device is in the freewheeling diode state, the RC-IGBT gate is in a low-level pulse, aiming to obtain a smaller on-state voltage drop. Before the power device exits the freewheeling diode state, the RC-IGBT gate is in a high-level pulse, so as to obtain low dynamic loss and optimize the on-state loss of the freewheeling diode.

[0103] What needs to be explained about the specific structure of the present invention is that the connection relationship between the various component modules adopted in the present invention is definite and feasible. Except for the special instructions in the embodiments, the specific connection relationship can bring about the corresponding technical effects, and solve the technical problems raised by the present invention without relying on the execution of the corresponding software program. Except for the specific instructions, the models and connection methods of the components, modules and specific components appearing in the present invention belong to the existing technologies such as published patents, published journal articles, or common knowledge that can be obtained by technical personnel in this field before the application date, and there is no need to elaborate, so that the technical solution provided in this case is clear, complete and feasible, and the corresponding physical products can be reproduced or obtained according to the technical means.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mine frequency converter control system based on RC-IGBT, comprising multiple main circuits and control units connected to each other, characterized in that: The main circuit comprises a power supply network, wherein the output end of the power supply network is connected in series with a network-side filter unit (11) and then connected to the AC side of a network-side RC-IGBT three-level rectifier unit (12); the DC side of the network-side RC-IGBT three-level rectifier unit (12) is connected in series with a DC bus support capacitor (13) through a wire and then connected to the DC side of a machine-side RC-IGBT three-level inverter unit (14); the AC side of the machine-side RC-IGBT three-level inverter unit (14) is connected in series with an AC filter inductor (15) and then connected to an AC synchronous motor (16); The control unit comprises a main control unit (21), a control signal acquisition unit (22), and a control signal sending unit (23); the signal input end of the main control unit (21) is connected to the control signal acquisition unit (22) via a wire; the main control unit (21) is connected to the control signal sending unit (23) via a VME bus, and a pulse trigger signal is sent to an optical fiber trigger board of the control signal sending unit (23); the optical fiber trigger board is connected to the RC-IGBT power devices of the grid-side RC-IGBT three-level rectifier unit (12) and the machine-side RC-IGBT three-level inverter unit (14) via optical fibers; The main control unit (21) outputs a desaturation control PWM pulse to drive each RC-IGBT power device in the switch unit to turn on and off; The main control unit (21) comprises a main control architecture based on DSP and FPGA, specifically comprising a host DSP, a slave DSP, and a slave FPGA, wherein data transmission is achieved between the host DSP and the slave DSP and the slave FPGA via an SPI communication interface; The main control unit (21) realizes full digital control of a dedicated platform for mining frequency converters based on RC-IGBT through a host DSP, a slave DSP, and a slave FPGA, and transmits control signals to RC-IGBT power devices through optical fibers through voltage and current digital closed-loop control and carrier phase shift modulation; The host DSP and the slave DSP are provided with a control algorithm implementation unit inside, and the sampling signal output by the control signal acquisition unit (22) is input into the host DSP through A / D conversion for operation, and the control algorithm implementation unit receives the sensor information after the sampling signal conditioning of the control signal acquisition unit (22), calculates the modulation signal according to the power given value, and then sends the pulse trigger signal to the optical fiber trigger board; The slave FPGA is used to complete the overvoltage, overcurrent, overtemperature protection and reverse conduction IGBT drive pulse trigger control algorithm for the dedicated platform of mining inverter; A mine frequency converter control method based on RC-IGBT comprises the following steps: Step 1: The host DSP triggers the desaturation control of the freewheeling diode of the slave FPGA by judging the reverse conduction state of the RC-IGBT in the initial IGBT mode; Step 2: After the freewheeling diode desaturation control is triggered, switch to the freewheeling diode mode, which can prevent the RC-IGBT from turning on; Step 3: Before turning off the freewheeling diode mode, reduce the effect of excessive storage charge of the freewheeling diode on dynamic loss by driving the gate to +15V, thereby reducing saturation; Step 4: During the desaturation time of the freewheeling diode, the freewheeling diode conduction mode with Vge=0V is set; Step 5: In the freewheeling diode mode, when the load current is detected to be zero-crossing, the RC-IGBT is turned on to achieve a smooth current transition from the freewheeling diode to the IGBT of the same power device; Step 6: In the IGBT mode, when the load current is detected to be crossing the zero point, the RC-IGBT is turned off to reduce the dynamic loss of the freewheeling diode.

2. According to claim 1, a mine frequency converter control system based on RC-IGBT is characterized in that: The main control unit (21) is also connected to the monitoring system, the Ethernet control module, the mining inverter dedicated platform, and the encoder through wires; The main control unit (21) realizes data transmission with the monitoring system through the Modbus communication protocol, and the monitoring system is provided with a human-machine interface; The main control unit (21) realizes data transmission with an Ethernet control module supporting network control via an SCI communication interface; The main control unit (21) is connected to a dedicated platform for a mine frequency converter via a CAN bus, and the dedicated platform for a mine frequency converter is provided with overvoltage, overcurrent and overtemperature protection.

3. The RC-IGBT-based mine frequency converter control system according to claim 2, characterized in that: The control signal acquisition unit (22) comprises a voltage sensor, a current sensor, and a temperature sensor for acquiring the operating temperature of the frequency converter, wherein the voltage sensor is used to detect three grid voltages, two DC side capacitor voltages, and three load voltages in real time, and the current sensor is used to detect three grid currents and three load currents in real time.

4. The RC-IGBT-based mine frequency converter control system according to claim 3, characterized in that: The grid-side RC-IGBT three-level rectifier unit (12) and the machine-side RC-IGBT three-level inverter unit (14) are both composed of three groups of neutral point clamped three-level power modules, and the neutral point clamped three-level power modules include: each phase bridge arm in the rectifier and inverter topology is composed of four RC-IGBT fully controlled devices with integrated freewheeling diodes and two clamping diodes, which are connected in parallel through high-voltage DC bus support capacitors and share a DC bus; The two ends of the clamping diode are connected with a clamping resistor for ensuring that the output end of the power unit is reliably clamped to a zero level, and the selected clamping resistor is specifically a water-cooled resistor.

5. The RC-IGBT-based mine frequency converter control system according to claim 4, characterized in that: The host DSP specifically adopts a model of TMS320F28335, the slave DSP specifically adopts a model of TMS320F28069F, and the slave FPGA specifically adopts a model of Sparten-6 FPGA; The voltage sensor is specifically AV 100-2000, the current sensor is specifically LF505 S SP13 (24V), and the temperature sensor is specifically DS18B20; The RC-IGBT in the neutral point clamped three-level power module adopts a model of 6500V / 1000A, and the clamping diode adopts a fast recovery diode of model D1331SH.

6. The RC-IGBT-based mine frequency converter control system according to claim 1, characterized in that: The specific judgment steps of the control method are as follows: 1) Determine the state of the current input PWM pulse. When the PWM pulse is on the rising edge, start the interlock timer with the set time. Before the interlock timer count ends, determine the reverse conduction state of the RC-IGBT, thereby obtaining the current operation mode of the RC-IGBT. 2) Judgment of the reverse conduction state of RC-IGBT: When Vce is at a low level, it is judged that the current state is a high-level freewheeling diode mode, the gate voltage is 0V, and then it is judged whether the current input PWM pulse is a rising edge. If the current input PWM pulse is a rising edge, the desaturation timer of the set time is started, and the gate voltage is +15V to alleviate the high carrier density and reduce the stored charge in the on state. After the desaturation time is over, the gate voltage is -15V. If the current input PWM pulse is not a rising edge, the load current zero point judgment is entered; when Vce is at a high level, it is judged that the current state is a high-level IGBT mode, the gate voltage is +15V, and then it is judged whether the current input PWM pulse is a falling edge. If the current input PWM pulse is a falling edge, the gate voltage is -15V. If the current input PWM pulse is not a falling edge, the load current zero point judgment is entered; 3) Load current zero point judgment: In the freewheeling diode mode, when the load current is detected to be zero-crossing, the RC-IGBT is turned on to achieve a smooth current transition from the freewheeling diode to the IGBT of the same power device; In IGBT mode, when the load current is detected to be zero-crossing, the RC-IGBT is turned off to reduce the dynamic loss of the freewheeling diode.

7. The RC-IGBT-based mine frequency converter control system according to claim 6, characterized in that: When the PWM pulse is on the rising edge, the setting time of the interlock timer is 20us; The setting time of the desaturation time timer is 19us.

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