CN-114765413-B - Fault diagnosis and automatic fault-tolerant system and method

CN114765413BCN 114765413 BCN114765413 BCN 114765413BCN-114765413-B

Abstract

The invention provides a fault diagnosis and automatic fault tolerance system and method, wherein the system comprises a main control module and N control modules, wherein the control modules are used for detecting whether a buck converter has faults and fault types according to a switching state and voltage values, when the buck converter is detected to work normally, a first control signal is sent to the main control module, the main control module is used for calculating working current instructions and staggered conduction angles of each buck converter according to the number M of received first control signals, the working current instructions and the staggered conduction angles are sent to the control module for outputting the first control signals, the M control modules are also used for forming a new daisy chain communication structure according to the working current instructions and the staggered conduction angles, driving the buck converter to work, locating faults rapidly, isolating faults, automatically updating current direct current and delayed conduction angle increment, realizing safe, reliable and automatic staggered operation of a hydrogen production power supply, and ensuring that output ripples of the hydrogen production power supply are always minimum.

Inventors

YANG WENQIANG
XING XIAOWEN

Assignees

国家能源投资集团有限责任公司
北京低碳清洁能源研究院

Dates

Publication Date: 20260505
Application Date: 20210115

Claims (8)

1. The fault diagnosis and automatic fault tolerance system is applied to a hydrogen production power supply with multiphase interlacing and multiple groups of switches connected in parallel, and the hydrogen production power supply comprises N buck converters which are arranged in parallel, and is characterized by comprising a main control module and N control modules; Each control module is used for being connected with one buck converter, and each control module is also connected with the main control module, wherein a detection pin of the control module is connected to a corresponding detection point of the buck converter; The control module is used for detecting the switching state of a switching tube in the buck converter and detecting the voltage value of a diode in the buck converter, detecting whether the buck converter has faults and the fault type according to the switching state and the voltage value, and sending a first control signal to the main control module when the buck converter is detected to work normally; The main control module is used for counting the number M of received first control signals, wherein M is less than or equal to N, working current instructions and staggered conduction angles of each buck converter are calculated according to the number M of received first control signals, wherein the working current instructions are obtained by equally dividing M into current instructions calculated by the main control module according to voltage-power droop control; The M control modules are further used for forming a new daisy chain communication structure according to the working current instruction and the staggered conduction angle to drive the buck converter to work; The control module is used for detecting whether the buck converter has faults and the fault type according to the switch state and the voltage value, and the principle is as follows: When s (t) =0 and U D （t）>U Dth1 are detected, determining that a short circuit fault occurs in the capacitor of the buck converter, wherein U Dth1 =U do +i Lover *r short , s (t) =0 represent that the switching tube is in an off state, U D (t) is the voltage of the diode, U Dth1 is the voltage threshold of the diode, i Lover is the inductor current overcurrent threshold, r short is the capacitor short circuit impedance, and U do is the inductor voltage; When s (t) =0 and U D (t) >0 are detected, determining that a short circuit fault occurs in the switching tube of the buck converter; When s (t) =1 and U D (t) >0 are detected, determining that all switching tubes of the buck converter have open faults, wherein s (t) =1 indicates that the switching tubes are in a closed state; When s (t) =1 and U th2 <U D (t) <0 are detected, determining that a short circuit fault occurs in a diode of the buck converter, wherein U th2 =-U in +r s *i s,max ,U in is an input voltage, and r s represents the internal resistance of a switching tube; When s (t) =0 and U D （t）>U th3 and U th3 =4U f,max , determining that all diodes of the buck converter are open-circuited, wherein U f,max is the maximum instantaneous forward voltage; The control module is further configured to detect a resistance value Z thIGBTi of the thermistor in the buck converter, and determine that an open circuit fault occurs in a diode of the buck converter when the resistance value Z thIGBTi >Z th130 is Z th130 is an open circuit threshold value of the thermistor at 130 ℃.
2. The fault diagnosis and automatic fault tolerance system according to claim 1, wherein each control module is provided with a communication unit, and the communication unit is used for realizing signal transmission between the control modules, so that the M control modules form a new daisy-chain communication structure according to the received operating current command and the staggered conduction angle.
3. The fault diagnosis and automatic fault tolerance system according to claim 1, wherein the control module is configured to send a second control signal to the main control module when the buck converter fault is detected, wherein the first control signal is a low level signal and the second control signal is a high level signal.
4. The system of claim 3, wherein each control module comprises an input-output switch, a nor gate, a logic determination unit, a control unit, and a resistor; The input end of the logic judging unit is used for being connected with the buck converter, the output end of the logic judging unit is connected with the first input end of the NOR gate, the second input end of the NOR gate is connected with a power supply through a resistor, the second end of the NOR gate is grounded through the input and output switch, the output end of the NOR gate is connected with the input end of the main control module, the output end of the main control module is connected with the input end of the control unit, the control unit is used for driving the buck converter to work, and the logic judging unit is used for judging whether the buck converter breaks down or not.
5. The system of any one of claims 1 to 4, wherein each buck converter includes a plurality of switching tubes, a plurality of diodes and inductors, the number of switching tubes is equal to the number of diodes, a first end of each switching tube is used for connecting with a positive pole of an input power source, a second end of each switching tube is respectively connected with a negative pole of the plurality of diodes, a negative pole of each diode is used for connecting with a negative pole of the input power source, a second end of each switching tube is also connected with a first end of the inductor, and second ends of the inductors are mutually connected.
6. The fault diagnosis and automatic fault tolerance system according to claim 5, wherein the switching tube is an IGBT.
7. The system of claim 5, wherein the number of buck converters is 9, and the number of switching tubes and diodes in each buck converter is 6.
8. A fault diagnosis and automatic fault tolerance method applied to the fault diagnosis and automatic fault tolerance system as claimed in any one of claims 1 to 7, comprising: Acquiring a switching state of a switching tube in the buck converter, and detecting a voltage value of a diode in the buck converter; detecting whether the buck converter has faults and fault types according to the switch state and the voltage value; counting the number M of the buck converters which normally work; According to the number M of the buck converters which normally work, calculating to obtain a working current instruction and an interleaving conduction angle of each buck converter; and sending the working current instruction and the staggered conduction angle to M control modules, so that the control modules form a new daisy chain communication structure according to the working current instruction and the staggered conduction angle, and drive the buck converter to work.

Description

Fault diagnosis and automatic fault-tolerant system and method Technical Field The invention relates to the technical field of power supplies, in particular to a fault diagnosis and automatic fault tolerance system method. Background The technology for producing hydrogen by using new energy is greatly developed, and has great significance for realizing energy transformation in China and accelerating the production and consumption of propulsion energy. With the continuous maturity of hydrogen production technology, the development of high-capacity hydrogen production equipment has become a future development trend. In order to match with large-capacity hydrogen production equipment, a stable and reliable hydrogen production power supply needs to be designed. The hydrogen production equipment adopts a direct current power supply mode, so that the reliability of the power supply equipment is improved, a simple buck converter circuit has incomparable advantages, but a single buck converter cannot be directly applied to a high-power occasion, and the staggered parallel structure can well solve the problem. For megawatt hydrogen production power supply, besides multiphase staggered parallel connection, the voltage resistance, the current resistance level, the highest junction temperature limit and the like of the switching devices on each branch are considered, and usually, a plurality of switching modules are still required to be connected in parallel for each phase of switch. The reliability and the safety of the hydrogen production power supply formed by multiphase interlacing and multiple groups of switches in parallel connection are the basis for ensuring the efficient operation of the electrolytic tank, and the hydrogen production power supply has the online fault detection and automatic fault tolerance capability. In the hydrogen production power supply, the capacitor short circuit fault is the most dominant fault type and is mainly caused by capacitor aging, so that the service life of the hydrogen production power supply is limited. In addition, the failure rate of the semiconductor switch is extremely high, and the failure rate can account for 30% -35% of the failure rate of the whole converter. Therefore, it is necessary to provide a fault diagnosis and automatic fault tolerance system and method for hydrogen production power supply. Disclosure of Invention In view of the foregoing, it is desirable to provide a fault diagnosis and automatic fault tolerance system, The fault diagnosis and automatic fault tolerance system is applied to a hydrogen production power supply with multiphase interlacing and multiple groups of switches connected in parallel, wherein the hydrogen production power supply comprises N buck converters which are arranged in parallel, and the system comprises a main control module and N control modules; Each control module is used for being connected with one buck converter, and each control module is also connected with the main control module; The control module is used for detecting the switching state of a switching tube in the buck converter and detecting the voltage value of a diode in the buck converter, detecting whether the buck converter has faults and the fault type according to the switching state and the voltage value, and sending a first control signal to the main control module when the buck converter is detected to work normally; The main control module is used for counting the number M of received first control signals, wherein M is less than or equal to N, calculating the working current instruction and the staggered conduction angle of each buck converter according to the number M of received first control signals, and sending the working current instruction and the staggered conduction angle to the control module for outputting the first control signals; And M control modules are also used for forming a new daisy chain communication structure according to the working current instruction and the staggered conduction angle and driving the buck converter to work. In one embodiment, the control module is configured to detect whether the buck converter fails or not and based on the switch state and the voltage value, the principle of the failure is as follows: When s (t) =0 and U D（t）>UDth1 are detected, determining that a short circuit fault occurs in the capacitor of the buck converter, wherein U Dth1=Udo+iL*rshort, s (t) =0 represent that the switching tube is in an off state, U D (t) is the voltage of the diode, U Dth1 is the voltage threshold of the diode, i L is the inductor current, and r short is the capacitor short circuit impedance; When s (t) =0 and U D (t) >0 are detected, determining that a short circuit fault occurs in the switching tube of the buck converter; When s (t) =1 and U D (t) >0 are detected, determining that all switching tubes of the buck converter have open faults, wherein s (t) =0 indicates that the switching tubes are in a closed state; When