CN118041324A - Wide-current-range composite high-efficiency quick change switch - Google Patents

Abstract

The invention discloses a composite high-efficiency fast switch with a wide current range, which comprises three-phase switch circuits, wherein each phase of switch circuit comprises four power tubes, a first power tube and a second power tube are connected in series on a first branch, a third power tube and a fourth power tube are connected in series on a second branch, and the first branch and the second branch are connected in parallel between a first alternating-current end and a second alternating-current end. According to the invention, the anti-series silicon carbide MOSFET power tube and the anti-series IGBT power tube are combined, so that the rapid switching function of a wide current range can be realized, the switching time reaches microsecond level, and the performance advantages of low power and high power scenes are considered, so that the current can automatically select a path, and the rapid switching switch can operate with low loss under different current levels.

Description

Wide-current-range composite high-efficiency quick change switch

Technical Field

The invention relates to the technical field of power systems, in particular to a composite high-efficiency fast change-over switch with a wide current range.

Background

In the field of intelligent power systems and load protection, the performance of conventional power switching devices directly affects the stability, efficiency and reliability of the system. Especially in the face of medium and large sensitive loads, such as medical equipment, data centers, etc., which are extremely low tolerant of blackout times, and sometimes even require power switching to be accomplished in the millisecond range to ensure critical operational continuity and data integrity. However, existing switching technologies, including conventional mechanical switching devices and thyristor-based fast-switching switches, all suffer from certain limitations.

The traditional mechanical switching device inevitably generates electric arcs in the opening and closing process of the physical contact points, which not only prolongs the switching time, but also increases the equipment loss and reduces the overall reliability of the system. In addition, the physical wear of the mechanical switch also limits its lifetime and stability, especially in high frequency switching applications. Thyristor-based fast-switching switches, while providing faster switching speeds, have limited their widespread use in high power applications due to inefficiency and high loss issues when handling large currents.

In view of the foregoing, there is a great need for a new switching device that can achieve fast and reliable switching while overcoming the limitations of conventional techniques in terms of speed, efficiency and reliability. Particularly, under different current levels, the optimal conductive path can be automatically selected to optimize the system performance and reduce the energy consumption, and the severe requirements of the modern intelligent power system and the sensitive load protection field are met.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, the invention aims to provide the composite high-efficiency fast switch with a wide current range, which combines the anti-series silicon carbide MOSFET power tube and the anti-series IGBT power tube, realizes the fast switch function with the wide current range, achieves microsecond level of switch time, and gives consideration to the performance advantages in low power and high power scenes, so that the current can automatically select a passage and can run with low loss under different current levels.

In order to achieve the above purpose, the invention is realized by the following technical scheme:

The utility model provides a compound high efficiency fast switch of wide current range includes three-phase switch circuit, and each phase switch circuit includes four power tubes, and wherein, first power tube and second power tube establish ties on first branch, and third power tube and fourth power tube establish ties on the second branch, first branch with the second branch connects in parallel between first AC end and second AC end.

Optionally, the first power tube and the second power tube are IGBT power tubes, and the third power tube and the fourth power tube are silicon carbide MOSFET power tubes.

Optionally, the emitter of the first power tube is connected with the emitter of the second power tube, the collector of the first power tube is connected with the first alternating current end, and the collector of the second power tube is connected with the second alternating current end; the source electrode of the third power tube is connected with the source electrode of the fourth power tube, the drain electrode of the third power tube is connected with the first alternating current end, and the drain electrode of the fourth power tube is connected with the second alternating current end.

Optionally, a first resistor and a second resistor are connected between the collector and the emitter of the first power tube and the second power tube; and a third resistor and a fourth resistor are connected between the drain electrode and the source electrode of the third power tube and the drain electrode and the source electrode of the fourth power tube.

Optionally, the first resistor to the fourth resistor are piezoresistors.

Optionally, each phase of switching circuit further includes a capacitor and a fifth resistor, where the capacitor and the fifth resistor are connected in series and then connected in parallel with the first branch and the second branch.

Optionally, each phase switching circuit further comprises a fast mechanical switch connected in parallel with the first and second branches.

Optionally, the first ac end is connected with an ac power source, the second ac end is connected with a load, or the first ac end is connected with a load, and the second ac end is connected with an ac power source.

Alternatively, the four power transistors are controlled by synchronous gate drive signals.

The invention has at least the following technical effects:

1. according to the invention, through the parallel operation of the two power tube devices, the system can keep high efficiency under different load conditions, wherein the low-loss characteristic of the silicon carbide MOSFET power tube can furthest reduce energy waste under the light load condition, and the conduction loss of the IGBT power tube is low under the heavy load condition, so that the system efficiency can be kept. The invention is capable of handling a variety of current levels, making it more adaptable and useful in different industrial and commercial applications.

2. The self-adaptive power supply has the self-adaptive characteristic without external control, the self-adaptive characteristic is realized through the intrinsic electrical characteristics of the silicon carbide MOSFET power tube and the IGBT power tube, and an external control system or complex driving logic is not needed for management, so that the circuit design is simplified, and meanwhile, the fault rate and the manufacturing cost are reduced.

3. In the aspects of system optimization and electric energy conversion efficiency, a designer can ensure that the circuit can realize optimal current distribution under different load conditions by optimizing the selection and configuration of the silicon carbide MOSFET power tube and the IGBT power tube. This not only improves the power conversion efficiency of the system, but also increases the reliability and durability of the fast switching switch as a whole, especially in the face of varying loads or operating conditions.

4. The invention has protection and stability, and the design also provides a built-in protection mechanism, so that the dependence on an additional protection circuit is reduced because the current naturally flows through the most suitable device. At the same time, this configuration ensures that the system remains stable even under high load conditions, reducing the risk of device damage due to current overload.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a schematic diagram of a one-phase circuit topology of a wide current range composite high efficiency fast switching switch according to an embodiment of the present invention.

Fig. 2 is a simulation diagram of automatic large-current shunt according to an embodiment of the present invention.

Fig. 3 is a simulation diagram of overvoltage suppression according to an embodiment of the present invention.

Detailed Description

The present embodiment is described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

A wide current range composite high efficiency fast switching switch of the present embodiment is described below with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of a one-phase circuit topology of a wide current range composite high efficiency fast switching switch according to an embodiment of the present invention. The fast change-over switch comprises three-phase switch circuits, as shown in fig. 1, each phase switch circuit comprises four power tubes, wherein a first power tube T1 and a second power tube T2 are connected in series on a first branch, a third power tube M1 and a fourth power tube M2 are connected in series on a second branch, and the first branch and the second branch are connected in parallel between a first alternating-current end P1 and a second alternating-current end P2.

The first power tube T1 and the second power tube T2 are anti-series IGBT (insulated gate bipolar transistor) power tubes, and the third power tube M1 and the fourth power tube M2 are anti-series silicon carbide MOSFET (metal-oxide semiconductor field effect transistor) power tubes.

The emitter of the first power tube T1 is connected with the emitter of the second power tube T2, the collector of the first power tube T1 is connected with the first alternating current end P1, and the collector of the second power tube T2 is connected with the second alternating current end P2; the source electrode of the third power tube M1 is connected with the source electrode of the fourth power tube M2, the drain electrode of the third power tube M1 is connected with the first alternating current end P1, and the drain electrode of the fourth power tube M2 is connected with the second alternating current end P2.

In addition, a first resistor MOV1 and a second resistor MOV2 are connected between the collector and the emitter of the first power tube T1 and the second power tube T2; and a third resistor MOV3 and a fourth resistor MOV4 are connected between the drain electrodes and the source electrodes of the third power tube M1 and the fourth power tube M2. The first resistor MOV1 to the fourth resistor MOV4 are piezoresistors.

Further, each phase of switching circuit further comprises a capacitor C and a fifth resistor R, and after the capacitor C and the fifth resistor R are connected in series, the capacitor C and the fifth resistor R are connected in parallel with the first branch and the second branch. Each phase switching circuit further comprises a fast mechanical switch PS connected in parallel with the first branch and the second branch.

The first ac terminal P1 is connected to an ac power source, the second ac terminal P2 is connected to a load, or the first ac terminal P1 is connected to a load, and the second ac terminal P2 is connected to an ac power source.

Specifically, each related switching circuit of the fast switching switch is formed by connecting three branches in parallel, namely a fast mechanical switching PS branch, a common source anti-series silicon carbide MOSFET power tube branch and a common emitter anti-series IGBT power tube branch.

Each phase switching circuit of the fast switch specifically comprises a fast mechanical switch PS, a first power tube T1, a second power tube T2, a third power tube M1, a fourth power tube M2, first to fourth resistors MOV1 to MOV4, a capacitor C and a fifth resistor R.

One end of the quick mechanical switch PS is connected with the first alternating current end P1, and the other end of the quick mechanical switch PS is connected with the second alternating current end P2; the drain electrode of the third power tube M1 is connected with the first alternating-current end P1, the source electrode of the third power tube M1 is connected with the source electrode of the fourth power tube M2, and the drain electrode of the fourth power tube M2 is connected with the second alternating-current end P2; the collector of the first power tube T1 is connected with the first alternating-current end P1, the emitter of the first power tube T1 is connected with the emitter of the second power tube T2, and the collector of the second power tube T2 is connected with the second alternating-current end P2.

In this embodiment, the first power tube T1 and the second power tube T2 are used to provide stable conductive paths in the middle-to-high current range, and the third power tube M1 and the fourth power tube M2 are used to provide low-loss conductive paths in the low-to-middle current range.

Further, each silicon carbide MOSFET power tube corresponds to one piezoresistor, and two ends of the piezoresistor are connected with a source electrode and a drain electrode of the silicon carbide MOSFET power tube; similarly, each IGBT power tube corresponds to one piezoresistor, and two ends of the piezoresistor are connected with a collector electrode and an emitter electrode of the IGBT power tube. The types of the four piezoresistors are the same.

Further, the capacitor C is connected in series with the fifth resistor R, the capacitor C is connected to the first ac terminal P1, and the fifth resistor R is connected to the second ac terminal P2.

It should be noted that the first ac terminal P1 may be connected to an ac power source, the second ac terminal P2 may be connected to a load, or the first ac terminal P1 may be connected to a load, and the second ac terminal P2 may be connected to an ac power source, i.e. the fast switch of the present embodiment has bi-directional transmissibility.

In addition, the fast change-over switch can be used in an alternating current scene or a direct current scene by matching with different detection methods.

Furthermore, the rapid mechanical switch PS plays an emergency role, and when the main solid-state switch (silicon carbide MOSFET power tube or IGBT power tube) fails and cannot work normally, the rapid mechanical switch PS can take over immediately, and the rapid mechanical switch PS can be closed to realize load power supply, so that further loss is avoided.

This configuration allows for a fast response and closing of the fast mechanical switch PS when the power system or load side needs to bypass the solid state switching elements to reduce losses, provide a more efficient power supply, ensuring a continuous and efficient power supply of the load, while maintaining the operation of the solid state switching elements in non-special cases to optimize the overall system performance with its fast switching capability in the microsecond order and automatic path selection functionality under different current conditions.

Furthermore, the four power tubes can adopt synchronous gate drive signals, so that the control mode can be further simplified, and the reliability of the quick change-over switch is improved. The specific working principle is as follows: when the fast switch is closed, the four power tubes are all conducted.

When the current is small, the on-resistance of silicon carbide MOSFET power transistors is low in the low current mode of operation, and therefore their voltage drop is also low. This makes silicon carbide MOSFET power transistors the preferred path for current flow at low currents, which means that current flow through silicon carbide MOSFET power transistors M1, M2 results in lower power losses at low currents, thereby improving the overall energy efficiency of the system.

As load current increases, the on-resistance of silicon carbide MOSFET power transistors increases, causing their tube voltage drop to increase as well. In contrast, IGBT power transistors have a relatively fixed saturation voltage drop. At a certain current level, the tube voltage drop of the silicon carbide MOSFET power tube exceeds the saturation voltage drop of the IGBT power tube. At this point the current starts to tend to flow through the IGBT power tubes because they now provide a lower voltage drop path.

Under high current conditions, the IGBT power transistors T1, T2 become the main path of current due to the relatively stable low saturation voltage drop of the IGBT power transistors. This distribution reduces the current that silicon carbide MOSFET power tubes are subjected to, thereby protecting them from overheating and potential damage, while also ensuring that the overall system is able to handle high currents efficiently, with a high current auto-shunt simulation diagram as shown in fig. 2.

Specifically, the silicon carbide MOSFET power tube and the IGBT power tube share one driving circuit, so that under different current conditions, the current can automatically select an optimal path through the silicon carbide MOSFET power tube or the IGBT power tube, and high-efficiency and low-loss operation in a low-to-high current range is realized. Under the low current condition, the current mainly passes through the silicon carbide MOSFET power tube due to the low-state resistance of the silicon carbide MOSFET power tube, and when the current is increased beyond a certain threshold value, the current automatically turns to the IGBT power tube, and the relatively fixed saturation voltage drop is utilized to process large current, so that the silicon carbide MOSFET power tube is protected from being damaged by the excessive current, and the stable and reliable operation of the whole system in a wide current range is ensured.

In this embodiment, because the on-state resistance of the silicon carbide MOSFET power tube is small, the tube voltage drop of the silicon carbide MOSFET power tube is smaller than the IGBT power tube under the condition of small current, and as the current increases, the tube voltage drop of the silicon carbide MOSFET power tube increases until it is larger than the saturation voltage drop of the IGBT power tube; and the saturation voltage drop of the IGBT power tube is a fixed value. Therefore, under a high-current scene, the IGBT power tube passes through most of current, and the silicon carbide MOSFET power tube only passes through a small part of current, so that the silicon carbide MOSFET power tube is protected, the loss is reduced, the heating is reduced, and the stability of the quick change-over switch is improved.

Further, the capacitor C and the fifth resistor R in the embodiment together form an RC absorption loop. When the silicon carbide MOSFET power tube and the IGBT power tube are switched from the on state to the off state, the inductance in the peripheral circuit will try to maintain the original current unchanged, which will create a voltage spike between the drain and source of the switching device, since the current cannot be stopped instantaneously. If left uncontrolled, this spike may be higher than the maximum withstand voltage of the device, causing damage. At the moment the switching device turns off, the inductance in the peripheral circuit starts to generate a high voltage across the switching device due to the sudden change of current. The RC circuit now provides a path for this abrupt current change, and current flows into the capacitor C to charge it. In this process, the capacitor C stores the energy released by the inductor, reducing the direct impact on the switching device. After the current decreases through the inductance, the capacitor C starts to discharge through the fifth resistor R. The function of the fifth resistor R is to dissipate the energy stored by the capacitor C in the form of heat, thereby reducing the energy in the circuit.

Furthermore, the piezoresistor is in a high-impedance state under normal working voltage, and the normal working of the circuit is hardly affected. When the switching tube is closed to generate voltage spike, the voltage in the circuit exceeds the threshold value of the piezoresistor, the piezoresistor is rapidly converted into a low-resistance state, and the excessive voltage is effectively short-circuited, so that the voltage spike is limited. By limiting voltage spikes, piezoresistors protect silicon carbide MOSFET power transistors and IGBT power transistors from excessive voltages, which is critical to extending the life of these devices and maintaining the reliability of the circuit, where the overvoltage suppression simulation diagram is shown in fig. 3. In some cases, the RC circuit may not be able to handle all types of voltage spikes alone, especially those that are very brief but of high amplitude. The varistor acts here, it can respond quickly and limit these spikes, providing an additional layer of security. In the circuit, the piezoresistor and the RC circuit form a double protection mechanism. The varistor provides fast response overvoltage protection, while the RC circuit handles the energy generated when the switching device is turned off.

In summary, the invention combines a silicon carbide MOSFET power device, an IGBT power device and a fast mechanical switch, and optimizes the on-state loss and breaking capacity under different current levels. The invention solves the problems of slow switching speed, arc generation in the switching-off process and the like of the traditional change-over switch through a reasonable hardware design and control method, and provides microsecond-level rapid switching capability. In addition, the switch can automatically select the optimal conductive path in a wide current range, so that loss is reduced, and the efficiency and reliability of the system are improved. In addition, the rapid mechanical switch PS is used as an emergency power supply path, so that uninterrupted power supply under special conditions is ensured. And the invention further improves the stability of the switch and the protection capability of the equipment by connecting the energy absorption loop with the optimal design in parallel with each power switch component. Furthermore, the invention not only simplifies the circuit structure and reduces the failure rate and the manufacturing cost, but also ensures the optimal performance of the circuit under different load conditions by optimizing the configuration of the silicon carbide MOSFET power device and the IGBT power device, and enhances the electric energy conversion efficiency, the reliability and the durability of the system.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

While the present invention has been described in detail through the foregoing description of the preferred embodiment, it should be understood that the foregoing description is not to be considered as limiting the invention. Many modifications and substitutions of the present invention will become apparent to those of ordinary skill in the art upon reading the foregoing. Accordingly, the scope of the invention should be limited only by the attached claims.

Claims (9)

1. The utility model provides a compound high efficiency fast switch over switch of wide current range, its characterized in that includes three-phase switch circuit, and each looks switch circuit includes four power tubes, and wherein, first power tube and second power tube establish ties on first branch, and third power tube and fourth power tube establish ties on the second branch, first branch with the second branch is parallelly connected between first AC end and second AC end.

2. The wide current range composite high efficiency fast switching switch of claim 1, wherein said first power tube and said second power tube are IGBT power tubes, and said third power tube and said fourth power tube are silicon carbide MOSFET power tubes.

3. The wide current range composite high efficiency fast switching switch of claim 2, wherein an emitter of said first power tube is connected to an emitter of said second power tube, a collector of said first power tube is connected to said first ac terminal, and a collector of said second power tube is connected to said second ac terminal; the source electrode of the third power tube is connected with the source electrode of the fourth power tube, the drain electrode of the third power tube is connected with the first alternating current end, and the drain electrode of the fourth power tube is connected with the second alternating current end.

4. The wide current range composite high efficiency fast switching switch of claim 3, wherein a first resistor and a second resistor are connected between the collector and the emitter of the first power tube and the second power tube; and a third resistor and a fourth resistor are connected between the drain electrode and the source electrode of the third power tube and the drain electrode and the source electrode of the fourth power tube.

5. The wide current range composite high efficiency fast switching switch of claim 4, wherein said first to fourth resistors are piezoresistors.

6. The wide current range composite high efficiency fast switching switch of claim 1, wherein each phase switching circuit further comprises a capacitor and a fifth resistor, said capacitor and said fifth resistor being connected in series and in parallel with said first leg and said second leg.

7. The wide current range compound high efficiency fast switching switch of claim 1, wherein each phase switching circuit further comprises a fast mechanical switch in parallel with the first leg and the second leg.

8. The wide current range, composite, high efficiency, fast switching switch of claim 1, wherein the first ac terminal is connected to an ac power source, the second ac terminal is connected to a load, or the first ac terminal is connected to a load, and the second ac terminal is connected to an ac power source.

9. The wide current range composite high efficiency fast switching switch of claim 1, wherein the four power transistors are controlled with synchronous gate drive signals.