CN-121983918-A - Bypass state feedback circuit and method for power module

CN121983918ACN 121983918 ACN121983918 ACN 121983918ACN-121983918-A

Abstract

A bypass state feedback circuit and method of a power module comprise a frequency generation module, a frequency division module, a coding and decoding module, two optical port driving modules and two bypass switch closing detection circuits, wherein the frequency generation module generates square waves, the frequency division module divides the frequency, the coding and decoding module decodes corresponding signals input by all input control ends, selects corresponding signals input by one data input end and converts the corresponding signals into frequency signals matched with the optical port driving modules, one ends of switching tubes of the two bypass switch closing detection circuits are connected with output ends of the coding and decoding modules, whether the switching tubes of the two bypass switch closing detection circuits are conducted or not is controlled respectively according to whether two auxiliary contacts of the bypass switch are closed or not, and input ends of the two optical port driving modules are connected with output ends of the coding and decoding modules to generate one optical port driving signal respectively to drive corresponding optical ports. The invention improves the overall reliability of the modular multilevel device.

Inventors

CHEN MINGJIE
ZHANG MENG
WANG HONGBIN
LIU CHENGZHU
HAN DI
FANG XUAN
LUO TIANYU

Assignees

北京电力设备总厂有限公司

Dates

Publication Date: 20260505
Application Date: 20260126

Claims (10)

1. The utility model provides a power module bypass state feedback circuit, includes frequency generation module, frequency division module, codec module, two optical port drive modules, two bypass switch closed detection circuit, its characterized in that: The frequency dividing module divides the square wave with the fixed frequency generated by the frequency generating module to generate a set number of frequency signals; The encoding and decoding module comprises an encoding chip, three state conversion circuits and a peripheral circuit, and a bypass trigger main power supply alarm signal, a bypass trigger auxiliary power supply alarm signal and a bypass drive board power supply state alarm signal are respectively input into the state conversion circuit; each state conversion circuit carries out level conversion on received corresponding signals and outputs signals which are matched with the input control end of the coding chip, each state conversion circuit output end is respectively connected with different input control ends of the coding chip, signals of each frequency generated by the frequency division module are respectively connected with different data input ends of the coding chip, the coding chip decodes the corresponding signals input by all the input control ends and selects one corresponding signal input by one data input end as output according to decoding, the output end of the coding chip is connected with the input end of the peripheral circuit, and the peripheral circuit carries out level conversion on the output of the coding chip and generates frequency signals which are matched with the optical port driving module; The two bypass switch closing detection circuits have the same structure and comprise a switching tube, one end of the switching tube of the two bypass switch closing detection circuits is connected with the output end of the encoding and decoding module, and the other end of the switching tube is grounded; Whether the switching tubes of the two bypass switches are switched on or not is respectively controlled according to whether the two auxiliary contacts of the bypass switches are switched on or off; the input ends of the two optical port driving modules are connected with the output ends of the encoding and decoding modules, and an optical port driving signal is generated to drive the corresponding optical port.
2. The power module bypass state feedback circuit of claim 1, wherein: the frequency generation module consists of a crystal oscillator (X1), a first pull-up resistor (R1) and a pi-type filter circuit; The first power supply (VCC) is connected to the input end of the pi-type filter circuit, one end of the first pull-up resistor (R1), a power pin of the crystal oscillator (X1) and the output end of the pi-type filter circuit are connected, and the other end of the first pull-up resistor (R1) is connected with an enabling pin of the crystal oscillator (X1); The pi-type filter circuit comprises a first capacitor (C1), a second capacitor (C2), a third capacitor (C3) and a first inductor (L1), wherein one end of the first inductor (L1) is connected with one end of the third capacitor (C3) to serve as an input end of the pi-type filter circuit, the other end of the first inductor (L1) serves as an output end of the pi-type filter circuit, the other end of the third capacitor (C3) is grounded, and the first capacitor (C1) and the second capacitor (C2) are connected between the other end of the first inductor (L1) and the ground in parallel.
3. The power module bypass state feedback circuit of claim 2, wherein: The fixed frequency is set according to the set expected feedback delay, and specifically comprises the following steps: The expected feedback delay is set as a, the number of filtering cycles after the receiving end collects square waves is n, the fixed frequency is greater than or equal to 128 times n and divided by a, and the receiving end is a board card connected with each optical port.
4. The power module bypass state feedback circuit of claim 1, wherein: the frequency division module generates signals with set number of frequencies, specifically: The frequency dividing module comprises a counter (U1), and signals with set number of frequencies are generated through different frequency division by the counter (U1) and output; Or the counter (U1) is used for carrying out different frequency division to generate signals with the set number of 1 frequency reduction and signals output by the frequency generation module form signals with the set number of 1 frequency to be output.
5. The power module bypass state feedback circuit of claim 1, wherein: the peripheral circuit includes a twenty-first current limiting resistor (R20), a fourth transistor (Q4), a sixteenth pull-up resistor (R16), and a twenty-fourth voltage dividing resistor (R24), comprising: The output signal (fiber_tir) of the coding chip (U2) is connected with the grid electrode of the fourth triode (Q4) through a twenty-first current limiting resistor (R20), a first power supply (VCC) is connected with the output signal (fiber_tir) of the coding chip (U2) through a sixteenth pull-up resistor (R16), a twenty-fourth voltage dividing resistor (R24) is connected between the grid electrode of the fourth triode (Q4) and the ground, the source electrode of the fourth triode (Q4) is grounded, and the drain electrode of the fourth triode (Q4) is the output of the coding and decoding module.
6. The power module bypass state feedback circuit of claim 1, wherein: the three state conversion circuits have the same structure and comprise a state conversion current-limiting resistor, a state conversion grounding resistor, a state conversion pull-up resistor and a state conversion triode; the input end of the state conversion circuit is connected with the grid electrode of the state conversion triode through a state conversion current-limiting resistor; The state conversion grounding resistor is connected between the grid electrode of the state conversion triode and the ground, the source electrode of the state conversion triode is grounded, the first power supply (VCC) is connected with the drain electrode of the state conversion triode through the state conversion pull-up resistor, and the drain electrode of the state conversion triode is used as the output end of the state conversion circuit.
7. The power module bypass state feedback circuit of claim 1, wherein: The bypass switch closing detection circuit further comprises a detection pull-up resistor, a detection current-limiting resistor, a detection voltage-dividing resistor and a detection protection diode; the control end of the switching tube is a grid electrode, and one end of the switching tube is a drain electrode, and the other end of the switching tube is a source electrode; the second power supply (VD) is connected with the other end of the corresponding auxiliary contact of the bypass switch through a detection pull-up resistor; The anode of the detection protection diode is grounded, and the cathode of the detection protection diode is connected with the grid electrode of the switching tube.
8. The power module bypass state feedback circuit of claim 1, wherein: the optical port driving module comprises an optical path driving current-limiting resistor, an optical path driving shunt resistor, an optical path driving filter capacitor, a protective diode and an anti-reflection diode; The second power supply (VD) is connected with the diode anode of the optical port TSM1 through the optical path driving current limiting resistor The signal fiber_FB output by the encoding and decoding module is connected with the cathode of an anti-reflection diode, the anode of the anti-reflection diode is connected with the diode cathode of the corresponding light port, the protection diode, the light path driving filter capacitor and the light path driving shunt resistor are connected in parallel at the two ends of the diode anode of the corresponding light port and the diode cathode of the corresponding light port, wherein the cathode of the protection diode is connected with the diode anode of the corresponding light port, and the anode of the protection diode is connected with the diode cathode of the corresponding light port.
9. A power module bypass state feedback method based on the circuit of any one of claims 1-8, comprising: acquiring a bypass driving plate power supply state, a bypass trigger main power supply state and a bypass trigger redundant power supply state; Selecting a target frequency signal from the signals for generating the set number of frequencies based on the bypass trigger main power supply state, the bypass trigger redundant power supply state and the bypass drive board power supply state; If the bypass switch is opened, two auxiliary contacts of the bypass switch are opened, switching tubes of the two bypass switch closing detection circuits are not conducted, driving signals with the same frequency as the target frequency signals are output by the two optical port driving modules, corresponding optical signals are emitted by the two optical ports when the driving signals are in a low level, when the bypass switch is closed, the auxiliary contacts are closed, the switching tubes of the bypass switch closing detection circuits are conducted, the two optical port starting modules output the low level, and the two optical ports are quite bright.
10. The power module bypass state feedback method of claim 9, wherein: the method comprises the steps of selecting a target frequency signal from signals for generating a set number of frequencies based on a bypass trigger main power supply state, a bypass trigger redundant power supply state and a bypass drive board power supply state, wherein the target frequency signal is specifically as follows: If the bypass trigger main power supply state is abnormal, the bypass trigger main power supply alarm signal is at a high level, otherwise, at a low level; if the power supply state of the bypass trigger is abnormal, the power supply auxiliary warning signal of the bypass trigger is high level and is low level on the contrary; the binary signal corresponding to the bypass trigger main power supply alarm signal is used as the lowest bit of a binary number, and the binary signal corresponding to the bypass trigger auxiliary power supply alarm signal is used as the next lowest bit of the corresponding binary number; The binary number is decoded into decimal numbers, the number of the decimal numbers is set to be 8, signals which generate the set number of frequencies are ordered from high to low according to the frequencies, and the decoded decimal numbers are the numbers of the ordered target frequency signals.

Description

Bypass state feedback circuit and method for power module Technical Field The invention belongs to the technical field of high-voltage direct-current transmission, and particularly relates to a bypass state feedback circuit and method of a power module. Background The modularized multi-level topology is widely applied to direct current power electronic devices such as high-voltage direct current converters, direct current energy consumption devices, reactive compensation equipment and the like due to the advantages of high modularization degree, strong design flexibility, easiness in expansion, low harmonic content, high fault tolerance and the like. To improve reliability and fault ride-through capability of the modular multilevel topology, bypass switches are configured inside each power module. When the module is abnormal, the bypass switch is closed to cut off the fault module from the main loop, so as to ensure that the direct current equipment continuously and normally operates. The bypass switch is driven by the bypass driving board card and feeds back the action state, and the state feedback not only affects the switching judgment of the unit, but also relates to the start-stop control and the protection logic execution of the whole converter, and has a key influence on the overall reliability of the power module and the modularized multi-level equipment. The power module bypass state typically employs an optical fiber feedback bypass state signal. The existing bypass switch acts to open and close, the feedback is carried out by the existence of light and no light of the light port, the feedback state is single, the power failure of the bypass driving plate and the general state of the bypass state feedback circuit of the power module with the disconnected bypass switch cannot be distinguished, and therefore the correct feedback of the bypass switch state cannot be sent to the upper control. The improved bypass switch state feedback is realized by constructing an oscillating circuit through a 555 chip and feeding back the opening and closing states of the bypass switch and the power supply states of the bypass drive board card by utilizing different oscillating frequencies of different charge and discharge loops. The method can distinguish the power failure of the bypass board and the opening and closing of the bypass switch, but the oscillation frequency is only tens kHz to hundreds kHz, the receiving end frequency judgment delay reaches ms level, the quick feedback of the state can not be realized, the influence of the precision of the resistance-capacitance element is avoided, and the frequency consistency is poor in batch production. Disclosure of Invention In order to solve the defects existing in the prior art, the invention provides a bypass state feedback circuit and a bypass state feedback method for a power module. The invention adopts the following technical scheme. The first aspect of the present invention provides a power module bypass state feedback circuit, which includes a frequency generating module, a frequency dividing module, a coding and decoding module, two optical port driving modules, and two bypass switch closing detection circuits, specifically: The frequency dividing module divides the square wave with the fixed frequency generated by the frequency generating module to generate a set number of frequency signals; The encoding and decoding module comprises an encoding chip, three state conversion circuits and a peripheral circuit, and a bypass trigger main power supply alarm signal, a bypass trigger auxiliary power supply alarm signal and a bypass drive board power supply state alarm signal are respectively input into the state conversion circuit; each state conversion circuit carries out level conversion on received corresponding signals and outputs signals which are matched with the input control end of the coding chip, each state conversion circuit output end is respectively connected with different input control ends of the coding chip, signals of each frequency generated by the frequency division module are respectively connected with different data input ends of the coding chip, the coding chip decodes the corresponding signals input by all the input control ends and selects one corresponding signal input by one data input end as output according to decoding, the output end of the coding chip is connected with the input end of the peripheral circuit, and the peripheral circuit carries out level conversion on the output of the coding chip and generates frequency signals which are matched with the optical port driving module; The two bypass switch closing detection circuits have the same structure and comprise a switching tube, one end of the switching tube of the two bypass switch closing detection circuits is connected with the output end of the encoding and decoding module, and the other end of the switching tube is grounded; Whether the switching tubes of the two byp