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CN-115208196-B - Buck-Boost converter integrating short-circuit protection function

CN115208196BCN 115208196 BCN115208196 BCN 115208196BCN-115208196-B

Abstract

The invention discloses a Buck-Boost converter with an integrated short-circuit protection function, which is characterized in that a discharging branch consisting of a capacitor and an inductor is added on the basis of a Buck-Boost circuit of the Buck-Boost converter with the protection function, the inductor in the Buck-Boost circuit is coupled with the inductor in the discharging branch, and the anode of a thyristor is connected with the source of a MOSFET in series, so that the problem of power quality reduction caused by the serial load of a circuit breaker is solved, and the volume of the whole system is reduced.

Inventors

  • LI WEILIN
  • FEI YUQING
  • LIU YUYANG
  • WANG YUFENG
  • LAN LIQIANG
  • PU FAN

Assignees

  • 西北工业大学

Dates

Publication Date
20260505
Application Date
20220712

Claims (8)

  1. 1. The Buck-Boost converter integrating the short-circuit protection function is characterized in that: The Buck-Boost converter with the protection function is characterized in that a discharge branch consisting of a capacitor and an inductor is added on the basis of a Buck-Boost circuit, the inductor in the Buck-Boost circuit is coupled with the inductor in the discharge branch, and the anode of a thyristor is connected with the source electrode of a MOSFET in series; the Buck-Boost converter integrating the short-circuit protection function comprises a topological structure, The topological structure comprises a direct current power supply, a MOSFET, a thyristor, a first diode and a coupling inductance module, wherein the coupling inductance module comprises a coupling inductance primary winding and a coupling inductance secondary winding, a first capacitor, a second capacitor, a load resistor, a first resistor, a second diode and a third diode, the positive electrode of the direct current power supply is connected with the drain electrode of the MOSFET, the source electrode of the MOSFET is connected with the anode of the thyristor, the cathode of the thyristor is connected with the cathode of the first diode, the first end of the first resistor and the first end of the coupling inductance module, the anode of the first diode is connected with the positive electrode of the first capacitor, the positive electrode of the second capacitor and the first end of the load resistor, the negative electrode of the first capacitor is connected with the second end of the coupling inductance module, the second end of the first resistor is connected with the cathode of the second diode, the anode of the second diode is connected with the third end of the coupling inductance module, the fourth end of the third diode, the anode of the direct current power supply, the negative electrode of the second capacitor and the second end of the load resistor, the negative electrode of the second capacitor is connected with the second end of the second capacitor, the second end of the second capacitor and the second end of the load resistor form an absorption capacity of the coupling inductance winding, and the second branch of the second capacitor is connected with the second side of the second inductor.
  2. 2. The Buck-Boost converter with integrated short-circuit protection function as claimed in claim 1, wherein the turns ratio of the primary winding of the coupling inductor to the secondary winding of the coupling inductor is 16:5.
  3. 3. The Buck-Boost converter with integrated short-circuit protection function according to claim 2, wherein the Buck-Boost converter is operated in four steps.
  4. 4. The Buck-Boost converter of claim 3, wherein, in said four steps of said operation, step one is: When the MOSFET is turned on, the primary winding of the coupling inductor is charged, the voltages of the primary winding L 1 and the secondary winding L 2 are V L1 ,V L2 respectively, V in is the input voltage, V C1 is the voltage of the first capacitor, V o is the output voltage, L m is the mutual inductance of the coupling inductance, k is the coupling coefficient of the coupling inductance, The voltage difference of the primary winding L 1 in the on time is , D is the duty cycle and T s is the switching period.
  5. 5. The Buck-Boost converter integrated with short-circuit protection function as claimed in claim 4, wherein, of said four steps of said operation, step one further comprises, When the MOSFET is turned off, the primary winding L1 of the coupling inductor is discharged, the second capacitor C L is charged, the voltage V o is generated at the two ends of the load resistor, and the voltages of the primary winding L 1 and the secondary winding L 2 are respectively , , The voltage difference of the primary winding L 1 in the turn-off time is , The method is based on the principle of volt-second equilibrium: When the switching frequency is very high, the current of the secondary winding branch through the coupling inductor is negligible, and the discharging branch has no influence on the normal working state.
  6. 6. The Buck-Boost converter integrated with a short-circuit protection function as claimed in claim 5, wherein, of said four steps of said operation, step two is, When a short circuit fault occurs, the load current can change greatly in a short time, and the first capacitor and the second capacitor start to discharge to provide fault current; When fault current flows through the secondary winding of the coupling inductor, the primary winding of the coupling inductor induces current with the direction opposite to that of steady-state working current, the induced current counteracts forward steady-state current gradually, the current flowing through the thyristor is gradually reduced, and when the current of the thyristor is smaller than 0 and reaches a reverse bias condition, the thyristor is turned off.
  7. 7. The Buck-Boost converter integrated with short-circuit protection function as claimed in claim 6, wherein, of said four steps of said operation, step three is, After the thyristor is turned off, the first capacitor, the second capacitor and the coupling inductance secondary winding form a passive resonant circuit; the system enters a passive LC resonance working state, at the moment, the discharge of the first capacitor and the second capacitor is finished, and the secondary winding of the coupling inductor starts to discharge.
  8. 8. The Buck-Boost converter integrated with short-circuit protection function as claimed in claim 7, wherein, of said four steps of said operation, step four is, When the secondary winding of the coupling inductor starts discharging, a part of current flows through the energy-absorbing circuit formed by the second resistor and the third diode, a part of current charges the first capacitor, the induced current of the primary winding of the coupling inductor flows through the energy-absorbing circuit formed by the first resistor and the second diode, and the third and fourth steps are repeated until the energy in the circuit is consumed, and fault isolation is completed.

Description

Buck-Boost converter integrating short-circuit protection function Technical Field The invention belongs to the technical field of direct current circuit breakers, and relates to a Buck-Boost converter with an integrated short-circuit protection function. Background Under the background of carbon neutralization and carbon peak, new energy is continuously propelled to generate and utilize, and the current electric industry development hot spot direction is achieved. The direct-current micro-grid has the advantages of simple structure, high power transmission efficiency, good electric energy quality and the like, new energy is connected into the grid in a direct-current mode, a converter can be reduced, and the control problem of voltage, frequency and phase is not needed to be considered, so that the direct-current micro-grid is an effective mode for connecting the new energy. A large number of DC-DC converters are needed to be used in the DC micro-grid to support the work of various electric appliances, and meanwhile, the large number of converters and electric appliances also put higher requirements on the safe operation of the DC micro-grid. However, the direct current does not have a natural zero crossing point, which increases the protection difficulty of the direct current system, so the short circuit protection of the direct current system is an important research direction of the current direct current power system. Dc circuit breakers are currently an effective dc protection method by creating artificial current zero crossings to isolate faults and extinguish arcs. The direct current circuit breaker can be divided into three types of mechanical type, hybrid type and solid type according to the structure. The mechanical breaker has high voltage and current level, but is limited by a mechanical switch, the switching speed is relatively low, the hybrid breaker forms a working mode that the mechanical switch is conducted to normally operate current, the solid-state device breaks short-circuit current, the solid-state device has good dynamic and static characteristics but has overlarge volume and weight, and the solid-state breaker takes a power electronic device as a switching element, so that the solid-state breaker has the advantages of small volume and weight, no arc, no light and no noise, and fault elimination, and is widely focused. Corzine K A et al in "Corzine K A,Ashton R W.Structure and analysis of the Z-source MVDC breaker[C]//2011IEEE Electric Ship Technologies Symposium.IEEE,2011:334-338." propose a Z source solid state circuit breaker developed based on a Z source converter that achieves the typical short circuit fault isolation required by the design of system parameters by simply adjusting the parameters of the circuit breaker elements without the need for additional detection and control circuitry. K.a. corzine et al in literature "K.A.Corzine and R.W.Ashton,A New Z-Source DC Circuit Breaker[J].IEEE Transactions on Power Electronics,2012,27(6):2796-2804." propose an interleaved, parallel Z-source solid state dc breaker. However, the power supply and the load of the cross-type circuit breaker are not grounded together, and the parallel-type circuit breaker has a problem of large fault current. Arthur h.chang et al in "CHANG A H,SENNETT B R,AVESTRUZ A T,et al.Analysis and design of DC system protection using Z-source circuit breaker[J].IEEE Transactions on Power Electronics,2015,31(2):1036-1049." propose a series Z source circuit breaker that solves the problems of both types of circuit breakers, but still produces a reflected current to the power supply when shorted. For this reason, li Weilin et al in "LI W,WANG Y,WU X,et al.A novel solid-state circuit breaker for on-board DC microgrid system[J].IEEE Transactions on Industrial Electronics,2018,66(7):5715-5723." propose a solid-state circuit breaker based on coupling inductance, which has the advantages of supporting the power load to be grounded in common, having no reflected current to the power, avoiding false triggering caused by abrupt load change, and the like. In practice, circuit breakers are typically connected in series between the converter and the load. But the passive components in the converter may oscillate with the passive components in the circuit breaker, degrading the output quality of the electrical energy. For this reason Xiaoguang Diao et al in "Diao X,Zhu W,Song Y,et al.An Integrated Design of the Solid-State Circuit Breaker and the DC-DC Converter[C]//2020IEEE Applied Power Electronics Conference and Exposition(APEC).IEEE,2020:3419-3423." propose a dc converter integrating a short-circuit protection function, reducing the losses of the circuit breaker to the quality of the power output by the converter. Kwen Chong et al in "A Buck Converter WITH INTEGRATED Circuit Breaker" propose a Buck Converter integrating a short-Circuit protection function, which reduces the volume of the system while ensuring the short-Circu