CN102427353B - A kind of IGBT series valve triggers monitoring system and communication means thereof - Google Patents

Abstract

The invention belongs to power electronics and field of power, be specifically related to a kind of IGBT series valve and trigger monitoring system and communication means thereof.This monitoring system includes valve base electronic device, IGBT driver element；Described valve base electronic device and IGBT driver element are connected by optical fiber；Described IGBT driver element and insulation bipolar-type power pipe IGBT electrical connection.To providing a kind of triggering and state reporting signal communication means between valve base electronic device VBE and the IGBT driver element of this monitoring system, the method is using optical fiber as communication media, ensure that the reliability of communication, and by certain coded system make triggering signal and state reporting signal have only to two optical fiber just can complete transmission, thus improve communication efficiency, reduce loss of communications, and ensure that connection number minimum between equipment, reduce optical fiber cost.

Description

An IGBT series valve trigger monitoring system and communication method thereof

technical field

The invention belongs to the field of power electronics and power systems, and in particular relates to an IGBT series valve trigger monitoring system and a communication method thereof.

Background technique

The semiconductor power switching device that appeared in the mid-1980s - the insulated gate bipolar power tube IGBT (Insulated Gate Biploar Transistor) is a composite device, its input control part is a MOSFET tube, and the output stage is a bipolar junction transistor , both the advantages of MOSFET tube and power transistor: high input impedance, voltage control, small driving power, fast switching speed, operating frequency up to 10-40kHz, lower saturation voltage, large voltage and current capacity, wide safe working area , but due to the priority of the voltage that a single IGBT device can withstand, it is difficult to meet the needs of high voltage and high power fields. In order to increase the voltage level of IGBT applications, the method of connecting IGBTs in series is usually used. With the gradual promotion of the application of power electronic technology in power systems, high-voltage valves based on IGBT series voltage equalization technology are becoming the core components of various new high-power power electronic devices, such as the voltage source converter type DC transmission system VSC-HVDC (Voltage VourceConverter Based HVDC), Static Synchronous Compensator STATCOM (Static Synchronous Compensator), Unified Power Flow Controller UPFC (Unified Power Flow Controller), etc.

The series structure of IGBT requires strict synchronization of the turn-on and turn-off of all IGBTs in the valve, otherwise the devices that are turned off in advance or turned on with delay will be subjected to overvoltage and cause device damage. In order to realize the synchronous turn-on and turn-off of IGBT, a valve-based electronic device must be added between the valve controller and the IGBT gate drive unit, and the trigger control signal generated by the valve controller is synchronously distributed to each IGBT in the valve. In addition, the IGBT gate drive unit is directly connected and installed on the IGBT, which is on the high-voltage side, while the valve-based electronic equipment is on the ground potential side, and the transmission of information between the two should be considered.

The commonly used IGBT driving method is to directly connect the pulse width modulation PWM trigger signal to the gate of the IGBT after necessary shaping and amplification processing. The characteristics of the PWM signal itself determine that it only contains two kinds of trigger control information, on and off, and it is shown as continuous high and low level alternation. This determines this PWM communication method. The line uses a high overhead to transmit a very low amount of information, resulting in low communication efficiency and large line loss. In the high-voltage IGBT series valve, in addition to the valve trigger pulse distribution link to transmit the PWM on and off signals to the IGBT drive unit, the IGBT drive unit also needs to transmit the IGBT working status report signal to the valve trigger pulse. The status report signal includes whether the IGBT is In the case of overvoltage, over dv/dt, loss of positive voltage, and short circuit faults, it is necessary to consider the transmission of signals. This problem can be solved by increasing the number of communication lines and transmitting various signals to be transmitted in parallel. However, in the field of high-voltage and high-power applications, each series valve corresponds to a valve-based electronic device, and each series valve contains The number of IGBTs is relatively large. For example, the series valve in a 300kV converter usually includes hundreds of IGBTs connected in series, and each IGBT corresponds to a drive unit. Simply relying on increasing the number of lines to increase the communication information capacity will lead to an increase in the number of line connections between devices, a large-scale interface circuit, and an increase in line costs.

Contents of the invention

The object of the present invention is to provide a trigger monitoring system for IGBT series valves and a communication method for triggering and status reporting signals proposed for the monitoring system in view of the increase in the number of line connections between devices, the large scale of interface circuits, and the increase in line costs. The communication method encodes various state return signals according to certain rules, and completes time-sharing transmission on one line. Since various IGBT faults occur at different times, this communication method will not affect the real-time performance of communication while increasing the amount of communication information, and can improve communication efficiency and reduce line loss. The principle of its communication method is mainly based on the different locations where overvoltage and overdv/dt faults, positive voltage loss faults, and short-circuit faults occur in each switching cycle of the IGBT and that various faults will not occur at the same time. Divide each IGBT switching cycle into several working periods, carry out corresponding fault detection in each working period, and transmit the fault detection information as a status report signal through the same optical fiber in time-sharing.

The object of the present invention is to adopt following technical scheme to realize:

An IGBT series valve trigger monitoring system, which is improved in that the monitoring system includes a valve-based electronic device VBE and an IGBT drive unit; the valve-based electronic device and the IGBT drive unit are connected through an optical fiber; the IGBT drive unit is connected to the Insulated bipolar power tube IGBT electrical connection.

A preferred technical solution provided by the present invention is: the valve-based electronic equipment VBE includes an encoding module, a decoding module, an optical transmitter and an optical receiver; the encoding module and the decoding module are realized by an FPGA control circuit.

The second preferred technical solution provided by the present invention is: the IGBT drive unit includes an optical receiver, an optical transmitter, a decoding module, a trigger circuit, a state detection module and a protection status report module; the optical transmitter and the optical receiver pass The optical fiber is respectively connected with the optical receiver and the optical transmitter of the valve-based electronic equipment; the decoding module, the status detection module and the protection status reporting module are realized by the FPGA control circuit.

The present invention provides a kind of communication method as above-mentioned monitoring system based on another object, and its improvement is that, described method divides each IGBT switch cycle into at least one working period according to the time that fault occurs; Said method Include the following steps:

A. The valve base electronic equipment VBE receives the PWM trigger pulse signal generated in the upper valve controller;

B. The encoding module converts the PWM trigger pulse signal and the IGBT working period information into an identifiable pulse signal of the IGBT drive unit according to the encoding method; the identifiable pulse signal is transmitted to the IGBT drive unit through an optical fiber;

C. The decoding module in the IGBT drive unit decodes the received identifiable pulse signal, so that the pulse signal is restored to the form before encoding, which is the PWM trigger pulse signal and the IGBT working period information;

D. The PWM trigger pulse signal analyzed by the IGBT drive unit from the code completes the triggering of the IGBT through the trigger circuit; the IGBT working period information is used for the IGBT drive unit to open the fault detection circuit corresponding to the working period to work on the IGBT The state is monitored in real time, and the detection result is converted into a state report code and fed back to the valve base electronic device VBE through the protection state report module; the real-time monitoring of the IGBT working state is realized by the state detection module;

E. The status reporting code expresses the fault detection result in the form of pulses, and the valve-based electronic equipment VBE receives the status reporting code, that is, the valve-based electronic equipment VBE decodes the working status of the IGBT according to whether the pulse is received and the time period when the pulse occurs.

A preferred technical solution provided by the present invention is: the encoding method of the trigger pulse signal and the IGBT working period information includes a method of counting delay of the valve base electronic device VBE and the IGBT drive unit.

Compared with prior art, the beneficial effect that the present invention reaches is:

1. In the monitoring system and its communication method provided by the present invention, the trigger signals of the IGBT series valves are synchronized to avoid overvoltage damage to devices due to asynchronous triggering.

2. In the monitoring system and its communication method provided by the present invention, the working status of the IGBT series valve is reported in real time to avoid damage to the device due to failure.

3. The monitoring system and its communication method provided by the present invention use optical fiber as the transmission medium for the trigger signal and the status report signal between the valve-based electronic equipment and the IGBT drive unit, which ensures the reliability and rapidity of communication, and realizes the communication between high and low voltage equipment. electrical isolation.

4. The monitoring system and its communication method provided by the present invention only use two optical fibers between the trigger distribution unit and the IGBT drive unit, which saves the number of optical fibers and the scale of the interface circuit, and reduces the cost and complexity of the equipment.

Description of drawings

Figure 1 is a schematic diagram of the overall hardware composition of the IGBT series valve trigger monitoring system;

Figure 2 is a schematic diagram of IGBT series valve trigger signal and IGBT working period information encoding and decoding;

Fig. 3 is a schematic diagram of the coding of the IGBT series valve state report signal.

detailed description

The specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

The schematic diagram of the overall hardware composition of the IGBT series valve trigger monitoring system involved in the present invention is shown in FIG. 1 . In Figure 1, the monitoring system includes the valve-based electronic equipment and the IGBT drive unit; the information channel between the valve-based electronic equipment and the IGBT drive unit uses two optical fibers as the transmission carrier, and the valve-based electronic equipment and the IGBT drive unit are equipped with Optical connections are optical transmitters and optical receivers. On the one hand, the optical fiber connection realizes the electrical isolation between the two devices. On the other hand, because the signal transmission loss on the optical fiber is small, the anti-interference is strong, and the transmission delay is small, the reliability of information transmission and IGBT triggering is guaranteed.

The valve-based electronic equipment includes an encoding module, a decoding module, an optical transmitter and an optical receiver, and the optical transmitter and the optical receiver are respectively connected to the IGBT drive unit optical receiver and optical transmitter through optical fibers; the encoding module and the decoding module can be realized through the FPGA control circuit Its function can also be realized by other control circuits.

The IGBT drive unit includes an optical receiver, an optical transmitter, a decoding module, a trigger circuit, a protection status reporting module, and a status detection module; the optical transmitter and the optical receiver are respectively connected to the optical receiver and the optical transmitter of the valve-based electronic equipment through optical fibers; the decoding The module, the protection state reporting module and the state detection module can realize their functions through the FPGA control circuit, and can also realize their functions through other control circuits; the trigger circuit is a circuit with some steady states or unsteady states, at least one of which is a steady state , and are designed to initiate the desired transition when an appropriate pulse is applied. The FPGA control circuit is mainly realized by the FPGA chip.

Specific working principle: The valve-based electronic device VBE receives the PWM trigger pulse generated by the upper-level valve controller. The coding module converts the PWM trigger pulse signal and the IGBT working period information into the pulse code that the IGBT drive unit can recognize according to the agreed coding method, and the recognizable pulse code is transmitted to the IGBT drive unit through the optical fiber channel, and the decoding module in the IGBT drive unit will The received pulse code is decoded to restore it to the form before encoding, which is the PWM trigger pulse signal and IGBT working period information. The PWM trigger pulse analyzed by the IGBT drive unit from the code completes the triggering of the IGBT through the trigger circuit; the IGBT working period information is used for the IGBT drive unit to open the fault detection circuit corresponding to the working period, monitor the IGBT working status in real time, and detect As a result, the conversion status report code is fed back to the valve base electronic equipment, and the valve base electronic device VBE receives the status report code through the optical fiber, and obtains the status information of each IGBT in the series valve through the decoding module.

The schematic diagram of encoding and decoding of IGBT series valve trigger signal and IGBT working period information is shown in Figure 2. The valve-based electronic equipment divides the switching cycle into several working periods by delay counting, etc., and synthesizes the working period information and PWM pulse signal into a trigger code and sends it to the IGBT drive unit; after receiving the code, the IGBT drive unit decomposes the PWM signal through the decoding module. Waveform and time period information. The schematic diagram of the IGBT series valve state report signal coding is shown in Figure 3. The status report code expresses the fault detection result in the form of pulses, and the decoding module of the valve-based electronic equipment decodes the working status of the IGBT according to whether the pulse is received and the time period when the pulse occurs; among them, the fault detection circuit is used to detect the possible process of the IGBT during the working process. The circuit for detecting voltage, over dv/dt, under voltage and short circuit faults can be realized by software and hardware.

There are many ways to encode the trigger pulse and the working period, and the valve-based electronic equipment and the IGBT drive unit can be respectively counted and delayed.

The invention provides a trigger and status report signal communication method between a valve-based electronic device and an IGBT drive unit. The communication method uses optical fiber as a communication medium to ensure the reliability of communication, and uses a certain coding method to make the trigger signal Only two optical fibers are needed to complete the transmission of the signal and the status return signal, thereby improving communication efficiency, reducing communication loss, and ensuring the minimum number of line connections between devices, reducing the cost of optical fibers.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application rather than to limit its protection scope. Although the present application has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: After reading this application, those skilled in the art can still make various changes, modifications or equivalent replacements to the specific implementation methods of the application. These changes, modifications or equivalent replacements are all within the scope of the pending claims of the application.

Claims (1)

1. A communication method of an IGBT series valve monitoring system, characterized in that, the IGBT series valve trigger monitoring system comprises a valve base electronic equipment VBE, an IGBT drive unit; the valve base electronic equipment and the IGBT drive unit are connected by an optical fiber; The IGBT drive unit is electrically connected to the insulated bipolar power transistor IGBT; The valve-based electronic equipment VBE includes an encoding module, a decoding module, an optical transmitter and an optical receiver; the encoding module and the decoding module are realized by an FPGA control circuit; The IGBT drive unit includes an optical receiver, an optical transmitter, a decoding module, a trigger circuit, a status detection module and a protection status reporting module; the optical transmitter and the optical receiver are respectively connected to the optical receiver and the optical The transmitter is connected; the decoding module, the status detection module and the protection status reporting module are realized by the FPGA control circuit; the method divides each IGBT switch cycle into at least one working period according to the time when the fault occurs; The method comprises the steps of: A. The valve base electronic equipment VBE receives the PWM trigger pulse signal generated in the upper valve controller; B. The encoding module converts the PWM trigger pulse signal and the IGBT working period information into an identifiable pulse signal of the IGBT drive unit according to the encoding method; the identifiable pulse signal is transmitted to the IGBT drive unit through an optical fiber; C. The decoding module in the IGBT drive unit decodes the received identifiable pulse signal, so that the pulse signal is restored to the form before encoding, which is the PWM trigger pulse signal and the IGBT working period information; D. The PWM trigger pulse signal analyzed by the IGBT drive unit from the code completes the triggering of the IGBT through the trigger circuit; the IGBT working period information is used for the IGBT drive unit to open the fault detection circuit corresponding to the working period to work on the IGBT The state is monitored in real time, and the detection result is converted into a state report code and fed back to the valve base electronic device VBE through the protection state report module; the real-time monitoring of the IGBT working state is realized by the state detection module; E. The state return code expresses the fault detection result in the form of a pulse, and the valve-based electronic device VBE receives the state return code, that is, the valve-based electronic device VBE decodes the working state of the IGBT according to whether the pulse is received and the period when the pulse appears; The encoding method of the trigger pulse signal and the IGBT working period information includes the method of counting delay of the valve base electronic device VBE and the IGBT driving unit.