CN107800179B - Shutdown energy recovery method and circuit - Google Patents
Shutdown energy recovery method and circuit Download PDFInfo
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- CN107800179B CN107800179B CN201711063497.1A CN201711063497A CN107800179B CN 107800179 B CN107800179 B CN 107800179B CN 201711063497 A CN201711063497 A CN 201711063497A CN 107800179 B CN107800179 B CN 107800179B
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- 238000011084 recovery Methods 0.000 title claims abstract description 76
- 238000000034 method Methods 0.000 title claims abstract description 37
- 239000003990 capacitor Substances 0.000 claims abstract description 148
- 238000004804 winding Methods 0.000 claims abstract description 24
- 238000004146 energy storage Methods 0.000 claims description 33
- 238000002955 isolation Methods 0.000 claims description 20
- 230000007423 decrease Effects 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 3
- 230000001360 synchronised effect Effects 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 6
- 230000000903 blocking effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other DC sources, e.g. providing buffering
- H02J7/345—Parallel operation in networks using both storage and other DC sources, e.g. providing buffering using capacitors as storage or buffering devices
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
- H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
- H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
- H02M3/325—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33507—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
- H02M3/33523—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
- H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
- H02M7/12—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/219—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
- Rectifiers (AREA)
Abstract
The invention provides a method and a circuit for turning off energy recovery, wherein the circuit for turning off energy recovery comprises a capacitor C1, a capacitor C2 and an AC-DC converter, wherein the AC-DC converter comprises a rectifier bridge B1 and a flyback circuit, and the flyback circuit comprises a primary side circuit formed by a primary side winding of a transformer T1 and a transformer T1 and a secondary side circuit formed by a secondary side winding of a transformer T1; one end of the capacitor C1 is led out to be used as a first input end for turning off the energy recovery circuit; the other end of the capacitor C1 is connected with one end of the capacitor C2, and the other end of the capacitor C2 is led out to be used as a second input end for turning off the energy recovery circuit; one end of the capacitor C2 is also connected with one alternating current input end of the rectifier bridge B1, and the other end of the capacitor C2 is also connected with the other alternating current input end of the rectifier bridge B1; the direct current output end of the rectifier bridge B1 is connected with a primary side circuit of the flyback circuit, and the output end of a secondary side circuit of the flyback circuit is led out to be used as the output end of the turn-off energy recovery circuit.
Description
Technical Field
The invention relates to a switch turn-off energy recovery method and a circuit thereof, in particular to a turn-off energy recovery method and a circuit thereof of a solid-state circuit breaker.
Background
Solid state circuit breakers generate losses in the overlap region of voltage and current during turn-off. A simpler method for reducing turn-off loss is to connect a capacitor in parallel with a switch, and reduce the voltage rising speed in the turn-off process of the switch through the capacitor, so as to reduce the overlapping area of voltage and current, thereby reducing the turn-off loss. Although this method can reduce the loss during turn-off, the energy stored in the capacitor is lost to the switch when the switch is turned on, increasing the turn-on loss. The turn-off energy is all converted to heat energy, resulting in an increase in the switch temperature.
Therefore, the current asymmetric half-bridge flyback circuit has the following problems:
(1) the switch turn-off loss is large;
(2) the turn-off energy is all converted to heat energy, resulting in an increase in the switch temperature.
Disclosure of Invention
In view of this, one of the technical problems to be solved by the present invention is to overcome the deficiencies of the existing methods, and provide a method for recovering turn-off energy, which stores the energy in the turn-off process of the switch, reduces the turn-off loss of the switch, and returns the stored energy to the external power supply terminal, thereby improving the efficiency of the whole system, and meanwhile, the added modules stop working step by step after the switch is turned off, and the steady-state process after the switch is turned off is not affected. Accordingly, another object of the present invention is to provide a switch-off energy recovery circuit.
The invention is a method for solving the technical problems as follows:
a switch-off energy recovery method of a switch utilizes an energy storage link to store the energy of switch-off, and adopts an energy feedback link to return the energy of the energy storage link to an external power supply end, and simultaneously adds a steady-state isolation link, so that an added switch-off energy recovery module is gradually cut off from the parallel connection relation with the switch after the switch is disconnected.
Correspondingly, the invention for solving the technical problems comprises the following steps:
a switch-off energy recovery circuit of a switch stores the energy of the switch-off by using a capacitor, returns the energy of an energy storage link to an external power supply end by using a switching power supply, and is isolated by adding the capacitor, so that an added switch-off energy recovery module is gradually cut off from the parallel connection relation with the switch after the switch is disconnected.
The invention particularly provides a turn-off energy recovery circuit which is suitable for turn-off energy recovery control of a switch and comprises a capacitor C1, a capacitor C2 and an AC-DC converter, wherein the AC-DC converter comprises a rectifier bridge B1 and a flyback circuit, and the flyback circuit comprises a transformer T1, a primary side circuit formed by a primary side winding of the transformer T1 and a secondary side circuit formed by a secondary side winding of the transformer T1; one end of the capacitor C1 is led out to be used as a first input end of the turn-off energy recovery circuit and is used for being connected with one end of the switch; the other end of the capacitor C1 is connected with one end of the capacitor C2, and the other end of the capacitor C2 is led out to be used as a second input end of the turn-off energy recovery circuit and is used for being connected with the other end of the switch; one end of the capacitor C2 is also connected with one alternating current input end of the rectifier bridge B1, and the other end of the capacitor C2 is also connected with the other alternating current input end of the rectifier bridge B1; the direct current output end of the rectifier bridge B1 is connected with a primary circuit of the flyback circuit, and the output end of a secondary circuit of the flyback circuit is led out to be used as the output end of the turn-off energy recovery circuit and is connected with an external power supply end.
Preferably, the primary side circuit of the flyback circuit further includes a switch G1, and the secondary side circuit further includes a diode D2; the direct-current output positive end of the rectifier bridge B1 is also connected with the synonym end of the primary winding of the transformer T1, the synonym end of the primary winding of the transformer T1 is connected with the drain of the switch G1, and the source of the switch G1 is connected with the direct-current output negative end of the rectifier bridge B1; the dotted terminal of the secondary winding of the transformer T1 is connected with the anode of the diode D2, and the cathode of the diode D2 is led out to be used as a first output terminal of the turn-off energy recovery circuit and is used for being connected with the anode of the external power supply terminal; and a second output end of the off energy recovery circuit is led out from the synonym end of the secondary winding of the transformer T1 and is used for being connected with the negative electrode of the external power supply end.
Preferably, the primary circuit of the flyback circuit further includes a capacitor C3, an anode of the capacitor C3 is connected to a positive dc output terminal of the rectifier bridge B1, and a cathode of the capacitor C3 is connected to a negative dc output terminal of the rectifier bridge B1.
Preferably, the capacitor C2 is a capacitor with piezoelectric effect, that is, the capacitance decreases with the increase of voltage.
The invention also provides a turn-off energy recovery circuit which is suitable for turn-off energy recovery control of a switch and comprises an energy storage module, a stable isolation module and an energy feedback module, wherein the stable isolation module is connected with the energy storage module in series to form a series branch, and two ends of the series branch are led out to be used as input ends of the turn-off energy recovery circuit and are connected with the switch in parallel; the input end of the energy feedback module is connected with the energy storage module in parallel, and the output end of the energy feedback module is led out to be used as the output end of the turn-off energy recovery circuit and is used for being connected with the external power supply end in parallel.
Preferably, the steady-state isolation module is composed of a capacitor C1; the energy storage module is composed of a capacitor C2; the energy feedback module is composed of an AC-DC converter, the AC-DC converter comprises a rectifier bridge B1 and a flyback circuit, and the flyback circuit comprises a primary side circuit formed by a primary side winding of a transformer T1 and a transformer T1 and a secondary side circuit formed by a secondary side winding of a transformer T1; one end of the capacitor C1 is led out to be used as a first input end of the turn-off energy recovery circuit and is used for being connected with one end of the switch; the other end of the capacitor C1 is connected with one end of the capacitor C2, and the other end of the capacitor C2 is led out to be used as a second input end of the turn-off energy recovery circuit and is used for being connected with the other end of the switch; one end of the capacitor C2 is also connected with one alternating current input end of the rectifier bridge B1, and the other end of the capacitor C2 is also connected with the other alternating current input end of the rectifier bridge B1; the direct current output end of the rectifier bridge B1 is also connected with a primary circuit of the flyback circuit, and the output end of a secondary circuit of the flyback circuit is led out to be used as the output end of the turn-off energy recovery circuit and is connected with an external power supply end.
In terms of method subject, the invention provides a turn-off energy recovery method, which is suitable for turn-off energy recovery control of a switch, and comprises the following steps of, an energy storage step, when a switch S1 is turned off, the turn-off current on a switch S1 is shunted to a series branch which is connected with a switch S1 in parallel and is composed of a capacitor C1 and a capacitor C2, and the capacitor C1 and a capacitor C2 store energy of turn-off energy; an energy feedback step, namely a feedback step of partially turning off energy, wherein after the switch S1 is turned off, the energy of the capacitor C2 is transmitted to a secondary circuit from a primary circuit through a flyback circuit of the AC-DC converter so as to feed back the partially turned-off energy to an external power supply end until the flyback circuit stops working; after the flyback circuit stops working, the capacitor C1 cuts off the parallel relation of the turn-off energy recovery circuit and the switch S1; in the step of feeding back the residual turn-off energy, after the switch S1 is turned on, the energy of the capacitor C1 and the capacitor C2 is transferred from the primary circuit to the secondary circuit through the flyback circuit of the AC-DC converter, so as to feed back the residual turn-off energy to the external power supply terminal.
Preferably, in the step of feeding back the residual turn-off energy, when the switch S1 is closed, the capacitor C1 and the capacitor C2 are in parallel connection, and the capacitor C1 and the capacitor C2 are charged and discharged, so that the voltages of the two are equal.
Preferably, in the energy feedback step, the operation starting time of the flyback circuit and the opening and closing action time of the switch S1 are kept synchronous, but the operation time period of the flyback circuit is fixed.
Preferably, in the energy feedback step, when the voltage of the capacitor C3 connected in parallel to the dc output terminal of the rectifier bridge B1 is greater than the operating voltage of the flyback circuit, the flyback circuit operates; when the voltage of the capacitor C3 is less than the operating voltage of the flyback circuit, the flyback circuit stops operating.
The invention also provides a turn-off energy recovery method which is suitable for turn-off energy recovery control of the switch, and comprises the following steps of energy storage, wherein when the switch S1 is turned off, the turn-off current on the switch S1 is shunted to a series branch which is connected with the switch S1 in parallel and consists of a steady-state isolation module and an energy storage module, and the energy storage module and the steady-state isolation module store energy for turn-off energy; an energy feedback step, namely a feedback step of partially turning off energy, wherein after the switch S1 is switched off, the energy of the energy storage module is fed back to an external power supply end through the energy feedback module until the energy feedback module stops working; after the energy feedback module stops working, the steady-state isolation module cuts off the parallel relation between the energy recovery circuit and the switch S1; and in the step of feeding back the residual turn-off energy, after the switch S1 is closed, the energy of the steady-state isolation module and the energy storage module is fed back to the external power supply end through the energy feedback module.
Preferably, the steady-state isolation module is composed of a capacitor C1; the energy storage module is composed of a capacitor C2; the energy feedback module is composed of an AC-DC converter, the AC-DC converter comprises a rectifier bridge B1 and a flyback circuit, and the flyback circuit comprises a primary side circuit formed by a primary side winding of a transformer T1 and a transformer T1 and a secondary side circuit formed by a secondary side winding of a transformer T1; in the energy storage step, when the switch S1 is turned off, the off current on the switch S1 is shunted to the series branch formed by the capacitor C1 and the capacitor C2 and connected with the switch S1 in parallel, and the capacitor C1 and the capacitor C2 store the off energy; a feedback step of partial cut-off energy, wherein after the switch S1 is switched off, the energy of the capacitor C2 is transmitted to a secondary circuit from a primary circuit through a flyback circuit of the AC-DC converter so as to feed back partial cut-off energy to an external power supply end until the flyback circuit stops working; after the flyback circuit stops working, the capacitor C1 cuts off the parallel relation of the turn-off energy recovery circuit and the switch S1; in the step of feeding back the residual turn-off energy, after the switch S1 is turned on, the energy of the capacitor C1 and the capacitor C2 is transferred from the primary circuit to the secondary circuit through the flyback circuit of the AC-DC converter, so as to feed back the residual turn-off energy to the external power supply terminal.
The switch-off energy recovery method has the beneficial effects that:
(1) the loss of the switch in the turn-off process is reduced;
(2) the state of the switch after being switched off is not influenced;
(3) the original turn-off loss is recovered and returned to the power supply end, so that the energy is recycled;
(4) the structure has strong universality and can be used for occasions with large switch-off energy.
Drawings
FIG. 1 is a functional block diagram of the turn-off energy recovery method of the switch of the present invention;
FIG. 2 is a schematic diagram of a first embodiment of the turn-off energy recovery circuit of the switch of the present invention;
fig. 3 is a graph showing the operation of the switch turn-off process of the first embodiment of the turn-off energy recovery circuit of the switch of the present invention;
fig. 4 is a graph showing the operation of the switch closing process of the first embodiment of the turn-off energy recovery circuit of the switch of the present invention.
Detailed Description
The invention adopts the conception that the energy of the switch off is stored by using the capacitor, the energy of the energy storage link is returned to the power supply end of the switch power supply by using the switch power supply, and meanwhile, the isolation capacitor is added, so that the added module does not influence the state of the switch after the switch off.
Fig. 1 is a schematic block diagram of a turn-off energy recovery method of a switch according to the present invention, which is composed of a steady-state isolation link, an energy storage link, and an energy feedback link. The stable isolation link is connected with the energy storage link in series and then connected to the switch in parallel; the input end of the energy feedback link is connected with the energy storage link in parallel, and the output end of the energy feedback link is connected with the external power supply end in parallel. The external power supply terminal is a power supply terminal of the switching power supply, or called a system power supply terminal, is located outside the turn-off energy recovery circuit of the invention, and belongs to an external terminal of the turn-off energy recovery circuit.
The method of fig. 1 is a schematic block diagram of a shutdown energy recovery circuit of the switch of the present invention, that is, the shutdown energy recovery circuit of the present invention is composed of a steady-state isolation module, an energy storage module, and an energy feedback module. The steady-state isolation module is connected with the energy storage module in series and then connected to the switch in parallel; the input end of the energy feedback module is connected with the energy storage module in parallel, and the output end of the energy feedback module is connected with the external power supply end in parallel.
First embodiment
Fig. 2 is a schematic diagram of a first embodiment of the turn-off energy recovery circuit of the switch of the present invention, in which a steady-state isolation module is formed by a capacitor C1, an energy storage module is formed by a capacitor C2, an energy feedback module is an AC-DC converter (or referred to as a switching power supply), the AC-DC converter includes a rectifier bridge B1 and a flyback circuit, the flyback circuit includes a primary circuit formed by a primary winding of a transformer T1 and a transformer T1, and a secondary circuit formed by a secondary winding of a transformer T1; the primary circuit of the flyback circuit further comprises a switch G1 and a capacitor C3, and the secondary circuit further comprises a diode D2.
The connection relationship of the first embodiment of the turn-off energy recovery circuit of the switch of the invention is as follows:
one end of the capacitor C1 is led out as a first input end of the turn-off energy recovery circuit, and is used for being connected with one end of the switch S1; the other end of the capacitor C1 is connected to one end of the capacitor C2, and the other end of the capacitor C2 leads out as a second input terminal for turning off the energy recovery circuit for connection to the other end of the switch S1. One end of the capacitor C2 is also connected with one alternating current input end of the rectifier bridge B1, and the other end of the capacitor C2 is connected with the other alternating current input end of the rectifier bridge B1; the positive electrode of the capacitor C3 is connected with the positive end of the direct current output of the rectifier bridge, and the negative electrode of the capacitor C3 is connected with the negative end of the direct current output of the rectifier bridge; the anode of the capacitor C3 is also connected with the synonym terminal of the primary winding of the transformer T1, the synonym terminal of the primary winding of the transformer T1 is connected with the drain of the switch G1, and the source of the switch G1 is connected with the cathode of the capacitor C3. The dotted terminal of the secondary winding of the transformer T1 is connected with the anode of the diode D2, and the cathode of the diode D2 is led out to be used as a first output terminal of the turn-off energy recovery circuit and is used for being connected with the anode of the power supply terminal; and a second output end of the shutdown energy recovery circuit is led out from the synonym end of the secondary winding of the transformer T1 and is used for being connected with the negative electrode of the power supply end.
Preferably, the capacitor C2 of the energy storage element may be a capacitor with piezoelectric effect, that is, the capacitance decreases with the increase of voltage. The reason for this is that 1) energy is lost from the energy storage link back to the external power supply, the less energy the energy storage link, the lower the loss, and for the same voltage, the smaller the capacitance, the less energy is stored and the lower the loss. 2) The larger the capacitance of the energy storage link is, the slower the voltage rising speed in the switch turn-off process is, and the smaller the switch turn-off loss is. 3) The turn-off process time of the switch is short, if the capacitance capacity is large, the voltage of the capacitor rises a little after the turn-off process of the switch is finished, so that the turn-off loss of the capacitor is reduced when the voltage of the capacitor is low, and the turn-off loss cannot be influenced after the voltage of the capacitor rises. 4) The three points show that the capacitance is large when the voltage is low and small when the voltage is high. This further reduces switching losses. But the capacitance of the capacitor C1 cannot be too small.
The energy feedback module can be a conventional flyback circuit module, and the conventional flyback circuit module comprises a capacitor C3, a switch G1, a transformer T1 and a diode D2. However, in the off energy recovery circuit, the capacitor C2 is already provided at the front stage of the flyback circuit module, and therefore the capacitor C3 may be optional.
The operating curve of the turn-off energy recovery circuit in the turn-off process of the switch S1 according to the first embodiment of the present invention is shown in fig. 3, and the operating principle of the turn-off process is as follows:
A. when the switch S1 is turned off from on, due to the existence of the capacitor C1 and the capacitor C2, and the capacitor C1 and the capacitor C2 are in series, a part of current on the switch S1 is shunted to a series branch formed by the capacitor C1 and the capacitor C2, and since the capacitor is equivalent to a short circuit in a transient state, the capacitor C2 and the capacitor C1 store energy for the shunted part of turn-off energy, so that the voltage across the switch S1 is slowly increased, and the switching loss is reduced;
B. after the switch S1 is turned off, a driving square wave is sent to the switch G1, so that the AC/DC flyback circuit module formed by the rectifier bridge B1, the capacitor C3, the switch G1, the transformer T1 and the diode D2 operates, and the energy of the capacitor C2 is fed back to the power supply terminal. Due to the direct current and alternating current blocking characteristic of the capacitor, in addition, the total time for sending the driving square waves to the switch G1 is fixed, along with the work of the AC/DC flyback circuit module, the voltage of the capacitor C2 is reduced, the voltage of the capacitor C1 is increased, when the capacitor C2 is reduced to a certain degree, the driving square waves stop, the flyback circuit stops working, and the voltages of the capacitor C1 and the capacitor C2 do not change any more. In this way, due to the existence of the capacitor C2, the AC/DC flyback circuit module stops working after the switch S1 is turned off; due to the existence of the capacitor C1, after the AC/DC flyback circuit module stops working, the DC blocking function is performed, and the parallel connection relationship between the entire turn-off energy recovery circuit including the AC/DC flyback circuit module and the capacitor C2 and the switch S1 is cut off. Therefore, steady-state isolation is realized, and the added turn-off energy recovery circuit stops working step by step after the switch S1 is turned off without influencing the state after the switch S1 is turned off.
During the turn-off process, the energy stored in the capacitors C1 and C2 is not fully fed back to the power supply terminal, the rest energy is fed back to the power supply terminal when the switch S1 is closed, the working curve of the switch S1 during the closing process is shown in fig. 4, and the working principle is as follows:
A. when the switch S1 is turned on, the capacitor C1 and the capacitor C2 are in parallel connection, and the voltages of the capacitor C1 and the capacitor C2 are different, so that the capacitor C1 and the capacitor C2 are charged and discharged to be equal to each other;
B. when the switch S2 is turned on, a driving square wave is sent to the switch G1, so that the AC/DC flyback circuit module formed by the rectifier bridge B1, the capacitor C3, the switch G1, the transformer T1, and the diode D2 operates to feed back the energy of the capacitors C1 and C2 to the power supply terminal. Since the total time to send the driving square wave to the switch G1 is fixed, the voltages of the capacitor C1 and the capacitor C2 decrease as the AC/DC flyback circuit module operates. When the driving square wave stops, the AC/DC flyback circuit module stops working, and the energy feedback process stops.
The capacitor C1 and the capacitor C2 in the circuit are in series connection in a transient state to form a series branch, and two ends of the series branch are connected with two ends of the switch S1 in parallel, so that the voltage rise of two ends of the switch S1 is slowed, and the switching loss is reduced. Two ends of the capacitor C2 are connected in parallel with the alternating current input end of the rectifier bridge B1, the direct current output end of the rectifier bridge B1 is connected with the primary side circuit of the flyback circuit, and the secondary side circuit of the flyback circuit is connected with the power supply end. The power supply end is the input end of the whole switching power supply. In this way, the off energy of the switch S1 can be fed back to the power supply terminal through the flyback circuit of the AC-DC converter. The turn-off energy is fed back to the supply terminal via the two operations of the flyback circuit, i.e. the operations at the closing and at the opening of the switch S1. The operation starting time of the flyback circuit and the two-time action time of the switch S1 are kept synchronous, namely when the switch S1 is turned off, the flyback circuit performs the first energy recovery operation, and when the switch S1 is turned on, the flyback circuit performs the second energy recovery operation. The operating time of the flyback circuit may be fixed. The circuit structure has strong universality and can be used for occasions with large switch-off energy.
Now, taking a certain breaker as an example, the input voltage is 1kV, the load is a constant-resistance load, and the current is 10A during normal operation. Without adding any device, the turn-off loss of the breaker switch is 1J. After the energy recovery circuit is turned off, the turn-off loss of a breaker switch is reduced to 0.36J, so that the turn-off loss is greatly reduced.
Second embodiment
The schematic diagram of the off energy recovery circuit of the switch of the second embodiment is the same as the first embodiment except for the control manner. The rectifier bridge B1, the capacitor C3, the switch G1, the transformer T1 and the diode D2 form an AC/DC flyback circuit module, the operation of which is independent and is determined by the voltage of the capacitor C3, independent of the control signal of the switch S1. When the voltage of the capacitor C3 is greater than the working voltage of the flyback circuit, the flyback circuit works, and when the voltage of the capacitor C3 is less than the working voltage of the flyback circuit, the flyback circuit stops working. With this configuration, an existing AC/DC module can be used without redesigning the circuit.
The above are merely preferred embodiments of the present invention, and those skilled in the art to which the present invention pertains may make variations and modifications of the above-described embodiments. Therefore, the present invention is not limited to the specific control modes disclosed and described above, and modifications and variations of the present invention are also intended to fall within the scope of the claims of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims (9)
1. The utility model provides a turn-off energy recuperation circuit, is applicable to the turn-off energy recuperation control of switch which characterized in that:
the direct current power supply comprises a capacitor C1, a capacitor C2 and an AC-DC converter, wherein the AC-DC converter comprises a rectifier bridge B1 and a flyback circuit, and the flyback circuit comprises a transformer T1, a primary side circuit formed by a primary side winding of the transformer T1 and a secondary side circuit formed by a secondary side winding of the transformer T1; wherein,
one end of the capacitor C1 is led out to be used as a first input end for turning off the energy recovery circuit; the other end of the capacitor C1 is connected with one end of the capacitor C2, and the other end of the capacitor C2 is led out to be used as a second input end for turning off the energy recovery circuit; one end of the capacitor C2 is also connected with one alternating current input end of the rectifier bridge B1, and the other end of the capacitor C2 is also connected with the other alternating current input end of the rectifier bridge B1; the direct current output end of the rectifier bridge B1 is connected with a primary side circuit of the flyback circuit, and the output end of a secondary side circuit of the flyback circuit is led out to be used as the output end of the turn-off energy recovery circuit.
2. A shutdown energy recovery circuit as claimed in claim 1, wherein: the primary side circuit of the flyback circuit further comprises a switch G1, and the secondary side circuit further comprises a diode D2; wherein,
the direct-current output positive end of the rectifier bridge B1 is also connected with the synonym end of the primary winding of the transformer T1, the synonym end of the primary winding of the transformer T1 is connected with the drain of the switch G1, and the source of the switch G1 is connected with the direct-current output negative end of the rectifier bridge B1;
the dotted terminal of the secondary winding of the transformer T1 is connected with the anode of the diode D2, and the cathode of the diode D2 is led out to be used as a first output terminal of the turn-off energy recovery circuit and is used for being connected with the anode of the external power supply terminal; and a second output end of the off energy recovery circuit is led out from the synonym end of the secondary winding of the transformer T1 and is used for being connected with the negative electrode of the external power supply end.
3. A shutdown energy recovery circuit as claimed in claim 2, wherein: the primary circuit of the flyback circuit further comprises a capacitor C3, the positive electrode of the capacitor C3 is connected with the positive direct-current output end of the rectifier bridge B1, and the negative electrode of the capacitor C3 is connected with the negative direct-current output end of the rectifier bridge B1.
4. A shutdown energy recovery circuit as claimed in any one of claims 1 to 3, wherein: the capacitor C2 is a capacitor with piezoelectric effect, that is, the capacitance decreases with the increase of voltage.
5. A turn-off energy recovery method is suitable for turn-off energy recovery control of a switch and comprises the following steps,
an energy storage step, when the switch S1 is turned off, the off current on the switch S1 is shunted to a series branch which is connected with the switch S1 in parallel and is composed of a capacitor C1 and a capacitor C2, and the capacitor C1 and the capacitor C2 store the off energy;
a step of energy feedback is carried out,
a feedback step of partial cut-off energy, wherein after the switch S1 is switched off, the energy of the capacitor C2 is transmitted to a secondary circuit from a primary circuit through a flyback circuit of the AC-DC converter so as to feed back partial cut-off energy to an external power supply end until the flyback circuit stops working; after the flyback circuit stops working, the capacitor C1 cuts off the parallel relation of the turn-off energy recovery circuit and the switch S1;
in the step of feeding back the residual turn-off energy, after the switch S1 is turned on, the energy of the capacitor C1 and the capacitor C2 is transferred from the primary circuit to the secondary circuit through the flyback circuit of the AC-DC converter, so as to feed back the residual turn-off energy to the external power supply terminal.
6. A shutdown energy recovery method as claimed in claim 5, characterized in that: in the step of feeding back the residual turn-off energy, when the switch S1 is turned on, the capacitor C1 and the capacitor C2 are in parallel connection, and the capacitor C1 and the capacitor C2 are charged and discharged to make the voltages of the two equal.
7. A shutdown energy recovery method as claimed in claim 5, characterized in that: in the energy feedback step, the working start time of the flyback circuit and the opening and closing action time of the switch S1 are kept synchronous, but the working time of the flyback circuit is fixed.
8. A shutdown energy recovery method as claimed in claim 5, characterized in that: in the energy feedback step, when the voltage of a capacitor C3 connected in parallel with the direct current output end of the rectifier bridge B1 is greater than the working voltage of the flyback circuit, the flyback circuit works; when the voltage of the capacitor C3 is less than the operating voltage of the flyback circuit, the flyback circuit stops operating.
9. A turn-off energy recovery method is suitable for turn-off energy recovery control of a switch and comprises the following steps,
in the energy storage step, when the switch S1 is turned off, the turn-off current on the switch S1 is shunted to a series branch which is connected with the switch S1 in parallel and is composed of a steady-state isolation module and an energy storage module, and the energy storage module and the steady-state isolation module store the turn-off energy;
a step of energy feedback is carried out,
a step of feeding back partial cut-off energy, wherein after the switch S1 is switched off, the energy of the energy storage module is fed back to the external power supply end through the energy feedback module until the energy feedback module stops working; after the energy feedback module stops working, the steady-state isolation module cuts off the parallel relation between the energy recovery circuit and the switch S1;
and in the step of feeding back the residual turn-off energy, after the switch S1 is closed, the energy of the steady-state isolation module and the energy storage module is fed back to the external power supply end through the energy feedback module.
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| CN201711063497.1A CN107800179B (en) | 2017-11-02 | 2017-11-02 | Shutdown energy recovery method and circuit |
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