Single-stage and double-stage switching type circuit

Abstract

The utility model discloses a single-stage and double-stage switching type circuit, which belongs to the technical field of electric energy conversion and comprises a first inductor, a second inductor, a third inductor, a three-phase rectifier bridge, a first control tube, a second control tube, a third control tube and a direct current regulation module, three input ends of the three-phase current bridge are respectively connected in series with the first inductor, the second inductor and the third inductor, and middle points of three bridge arms of the three-phase rectifier bridge are respectively connected with an input end of the direct current adjusting module after passing through the first control tube, the second control tube and the third control tube. The output end of the direct current adjusting module is connected with the load; according to the invention, the single-stage and double-stage rectification conversion circuit can be switched according to needs.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric energy conversion, and particularly to a single-stage and double-stage switching circuit. BACKGROUND

[0002] The single-stage rectifier circuit has relatively simple circuit structure, low cost, and less space required, and is suitable for miniaturized applications, but the range of input voltage cannot be too wide, and cannot meet the demand of wide voltage input range; the two-stage rectifier circuit has relatively smooth output voltage, small ripple, stable output voltage, and high efficiency, but the design is relatively complex, and the cost is increased. SUMMARY

[0003] The present application aims to provide a single-stage and double-stage switching circuit capable of switching between single-stage and double-stage as required.

[0004] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows: a single-stage and double-stage switching circuit, comprising: a first inductor, a second inductor, a third inductor, a three-phase rectifier bridge, a first control tube, a second control tube, a third control tube, and a DC regulating module; three input ends of the three-phase rectifier bridge are connected in series with the first inductor, the second inductor, and the third inductor, respectively, and the midpoints of the three bridge arms of the three-phase rectifier bridge are connected with the input end of the DC regulating module after passing through the first control tube, the second control tube, and the third control tube, respectively, and the output end of the DC regulating module is connected with a load.

[0005] Optionally, the single-stage and double-stage switching circuit further comprises a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first switch, and a second switch, the first capacitor is connected in parallel with the series branch of the third capacitor and the first switch, the second capacitor is connected in parallel with the series branch of the fourth capacitor and the second switch, and the second control tube is connected with the midpoint of the series branch of the first capacitor and the second capacitor.

[0006] Optionally, the DC regulating module comprises a first DC regulating unit and a second DC regulating unit, the output ends of the first DC regulating unit and the second DC regulating unit are connected in parallel and connected with a load, the first DC regulating unit is connected in parallel with the series branch of the third capacitor and the first switch, the second DC regulating unit is connected in parallel with the series branch of the fourth capacitor and the second switch, and the first DC regulating unit and the second DC regulating unit have the same half-bridge resonant circuit topology structure.

[0007] Optionally, the first capacitor and the second capacitor are high-frequency decoupling capacitors, the third capacitor and the fourth capacitor are electrolytic capacitors, and the first inductor, the second inductor, and the third inductor are PFC inductors.

[0008] Optionally, the direct current regulating module is a DC / DC resonant circuit, and the DC / DC resonant circuit comprises a three-level T-type full-bridge unit, a resonant unit and an output rectifier filter unit.

[0009] Optionally, the single-stage and double-stage switching circuit further comprises a first capacitor, a second capacitor, a first switch and a second switch, the second control tube is connected with the bridge arm midpoint of the three-level T-type full-bridge unit through the midpoint of the series branch of the first capacitor and the first switch and the midpoint of the series branch of the second capacitor and the second switch, the rectifier filter unit is connected in parallel with the output end of the resonant unit, and the first inductor, the second inductor and the third inductor are PFC inductors.

[0010] Optionally, the single-stage and double-stage switching circuit further comprises a first capacitor, a second capacitor and a third capacitor, the second control tube is connected with the bridge arm midpoint of the three-level T-type full-bridge unit through the midpoint of the series branch of the first capacitor and the second capacitor, the third capacitor is connected in parallel with the output end of the three-phase rectifier bridge, and the rectifier filter unit is connected in parallel with the output end of the resonant unit.

[0011] Optionally, in any single-stage and double-stage switching circuit, the first switch and the second switch are MOS tubes or relays, and the first control tube, the second control tube and the third control tube are switch tubes.

[0012] The scheme provided in the application can switch the two-stage rectification conversion circuit scheme to a single-stage scheme with higher efficiency, or switch the single-stage rectification conversion circuit scheme to a two-stage scheme with a wider input voltage range, so as to switch the single-stage and double-stage rectification conversion circuit according to needs.

[0013] In order to make the above features and advantages of the application more obvious and easy to understand, the following embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The circuit diagram of a first embodiment of the single-stage and double-stage switching circuit of the application.

[0015] Figure 2 The circuit diagram of a second embodiment of the single-stage and double-stage switching circuit of the application.

[0016] Figure 3 The circuit diagram of a third embodiment of the single-stage and double-stage switching circuit of the application.

[0017] In the drawings, similar reference numerals refer to similar elements. DETAILED DESCRIPTION

[0018] In order to make the technical scheme of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0019] In the first embodiment of the present application, please refer to Figure 1 A single-stage dual-stage switching circuit, comprising: inductance L1, inductance L2, inductance L3, three-phase rectifier bridge 11, control tube Sy1, control tube Sy2, control tube Sy3 and DC regulating module 12; the three input ends of the three-phase rectifier bridge 11 are connected in series with the inductance L1, the inductance L2 and the inductance L3, the three bridge arm midpoints of the three-phase rectifier bridge 11 are connected with the input end of the DC regulating module 12 after passing through the control tube Sy1, the control tube Sy2 and the control tube Sy3, and the output end of the DC regulating module 12 is connected with the load.

[0020] As an example, one end of the inductance L1 away from the three-phase rectifier bridge 11 is connected with the μ A phase of three-phase power, one end of the inductance L2 away from the three-phase rectifier bridge 11 is connected with the μ B phase of three-phase power, and one end of the inductance L3 away from the three-phase rectifier bridge 11 is connected with the μ C phase of three-phase power.

[0021] As an example, the three-phase rectifier bridge 11 comprises: diodes D1-D6, the input end of the three-phase rectifier bridge 11 connected in series with the inductance L1 is connected between the anode of the diode D1 and the cathode of the diode D4, the input end of the three-phase rectifier bridge 11 connected in series with the inductance L2 is connected between the anode of the diode D2 and the cathode of the diode D5, the input end of the three-phase rectifier bridge 11 connected in series with the inductance L3 is connected between the anode of the diode D3 and the cathode of the diode D6, the cathode of the diode D1 is connected with the cathode of the diode D3 through the cathode of the diode D2, and the anode of the diode D4 is connected with the anode of the diode D6 through the anode of the diode D5.

[0022] As an example, the single-stage dual-stage switching circuit further comprises capacitors C1, C2, C3, C4, switches S1 and S2, the capacitor C3 is connected in parallel with the series branch of the capacitor C1 and the switch S1, the capacitor C4 is connected in parallel with the series branch of the capacitor C2 and the switch S2, and the control tube Sy2 is connected with the midpoint of the series branch of the capacitor C3 and the capacitor C4.

[0023] As an example, the direct current regulating module 12 includes direct current regulating units 121 and 122, outputs of the direct current regulating units 121 and 122 are connected in parallel to a load, the direct current regulating unit 121 is connected in parallel to a series branch of a capacitor C1 and a switch S1, the direct current regulating unit 122 is connected in parallel to a series branch of a capacitor C2 and a switch S2, the direct current regulating units 121 and 122 in this embodiment are preferably identical half-bridge resonant circuit topologies.

[0024] In the formula, the capacitor C1 and the capacitor C2 are Bus electrolytic capacitors, the capacitor C3 and the capacitor C4 are high-frequency decoupling capacitors, the inductors L1, L2 and L3 are PFC inductors, the switches S1 and S2 are MOS tubes or relays, and the control tubes Sy1, Sy2 and Sy3 are bidirectional switching tubes.

[0025] As an example, the load in this embodiment is represented by a capacitor C0 and a resistor R0.

[0026] As an example, the direct current regulating unit 121 includes a switch S3, a switch S4, a capacitor C5, a transformer T1, a diode D7 and a diode D8, a series branch of the switch S3 and the switch S4 is connected in parallel to a series branch of the capacitor C1 and the switch S1; the transformer T1 includes a primary winding N1, a secondary winding N2 and a secondary winding N3; a series branch of the primary winding N1 of the transformer T1 and the capacitor C5 is connected in parallel to the switch S4, a series branch of the secondary winding N2 and the secondary winding N3 of the transformer T1 is connected in parallel to the diode D7 and the diode D8, a midpoint of the series branch of the secondary winding N2 and the secondary winding N3 of the transformer T1 is connected to the load, and anodes of the diode D7 and the diode D8 are connected in parallel to the load.

[0027] As an example, the direct current regulating unit 122 includes a switch S5, a switch S6, a capacitor C6, a transformer T2, a diode D9 and a diode D10, a series branch of the switch S5 and the switch S6 is connected in parallel to a series branch of the capacitor C2 and the switch S2; the transformer T2 includes a primary winding N4, a secondary winding N5 and a secondary winding N6; a series branch of the primary winding N4 of the transformer T2 and the capacitor C6 is connected in parallel to the switch S6, a series branch of the secondary winding N5 and the secondary winding N6 of the transformer T2 is connected in parallel to the diode D9 and the diode D10, a midpoint of the series branch of the secondary winding N5 and the secondary winding N6 of the transformer T2 is connected to the load, and anodes of the diode D9 and the diode D10 are connected in parallel to the load.

[0028] As an example, when the input low voltage, for example, 304~375Vac, switch S1, S2 is closed, the capacitor C1, capacitor C2 is connected to the circuit, at this time the circuit is two stage circuit of rectifier circuit series resonant circuit, the capacitor C1, capacitor C2 is the energy storage filter of the voltage regulation circuit. Three-phase alternating current is input to three-phase rectifier bridge 11 through inductance L1, inductance L2 and inductance L3, diode D1, diode D3 and diode D5 are turned on during the positive half cycle to rectify the alternating voltage into direct current voltage, diode D2, diode D4 and diode D6 are turned on during the negative half cycle to rectify the alternating voltage into direct current voltage, control tube Sy1, control tube Sy2 and control tube Sy3 are switched on in the circuit, according to the current direction, connected to P or N, capacitor C1, capacitor C2, capacitor C3 and capacitor C4 are current anti-interference and filtering, attenuate low frequency component and bus ripple, output stable voltage for the direct current regulation module 12, high frequency switching switch S3, switch S4, switch S5, switch S6, the rectified voltage and 0 level are input to direct current regulation unit 121 and direct current regulation unit 122, and the resonant cavity is used to provide soft switching for high frequency switch; for example, when the frequency of switch S3 and switch S4 is equal to the resonant frequency of the resonant cavity, the current on the primary side winding of transformer T1 decreases, and the output voltage also decreases accordingly; when the frequency of switch S3 and switch S4 is lower than the resonant frequency, the current on the primary side winding of transformer T1 increases, and the output voltage increases, the output direct current voltage of the former stage is converted into direct current voltage suitable for the load demand.

[0029] As an example, when the input voltage is a typical voltage and a high voltage, for example, 375V~456Vac, the switch S1 and the switch S2 are turned off, the capacitor C1 and the capacitor C2 are disconnected from the circuit, the inductor L1, the inductor L2 and the inductor L3 work as the differential mode inductors of the input and work in the single-stage circuit, at this time, the control tube Sy1, the control tube Sy2 and the control tube Sy3 are turned on at the moment when the two-phase voltages intersect, the phase with the larger amplitude in the positive direct current voltage is connected to the P end through the diode D1, the diode D3 or the diode D5, the phase with the larger amplitude in the negative direct current voltage is connected to the N end through the diode D2, the diode D4 or the diode D6, the control tube of the phase with the larger absolute value of the amplitude in the intersecting two-phase voltage is turned off, the remaining phase is connected to the Y end through the turned-on control tube Sy2, and the high-frequency components are further attenuated through the capacitor C3 and the capacitor C4, the input current of the high-frequency switching switch S3, the switch S4, the switch S5 and the switch S6 is input to the direct current regulating module 12, and a stable and safe voltage is output for the load; since the control tube Sy1, the control tube Sy2 and the control tube Sy3 are low-frequency switching at this time, there is no switching loss, the diodes D1~D6 of the three-phase rectifier bridge 11 and the inductors L1, L2 and L3 do not have high-frequency current passing through, and the inductors L1, L2 and L3 also have little core loss, so that the efficiency of the entire circuit is improved, and the peak efficiency can be improved by about 1%. According to the embodiment, the rectification scheme is selected according to the input voltage, the capacitor C1 and the capacitor C2 are connected to the circuit or not through the switch S1 and the switch S2, and the two-stage rectification circuit is switched to the single-stage rectification circuit, so that the peak efficiency of the circuit is improved.

[0030] In the second embodiment of the present application, please refer to Figure 2 The present application also provides a single-stage and two-stage switching circuit, wherein the direct current regulating module adopts a DC / DC resonant circuit 22, the DC / DC resonant circuit 22 comprises a three-level T-type full-bridge unit 221, a resonant unit 222 and an output rectification and filtering unit 223.

[0031] As an example, the single-stage and two-stage switching circuit further comprises the capacitor C1, the capacitor C2, the switch S1, the switch S2, the control tube Sy2 is connected to the bridge arm midpoint of the three-level T-type full-bridge unit 221 through the midpoint of the series connection of the capacitor C1 and the switch S1 and the series connection of the capacitor C2 and the switch S2, and the output end of the rectification and filtering unit 223 is connected to the input end of the resonant unit 222.

[0032] As an example, the three-level T-type full-bridge unit 221 includes switches S7-S14, the drain of bidirectional switch S7 and the drain of bidirectional switch S9 are connected to Y terminal, the source of bidirectional switch S7 is connected to the source of bidirectional switch S8, the source of bidirectional switch S9 is connected to the source of bidirectional switch S10; the drain of bidirectional switch S8 is connected to the source of bidirectional switch S11 and the drain of bidirectional switch S13, and is connected to the first input terminal of the resonance unit 222; the drain of bidirectional switch S10 is connected to the source of bidirectional switch S12 and the drain of bidirectional switch S14, and is connected to the second input terminal of the resonance unit 222, the drains of switches S11 and S12 are connected to P terminal, and the sources of switches S13 and S14 are connected to N terminal.

[0033] As an example, the resonance unit 222 includes inductance Lr, inductance Lm, capacitor Cr and transformer T3, inductance Lr is connected to Y terminal through bidirectional switches S7 and S8, capacitor Cr is connected to Y terminal through bidirectional switches S9 and S10, inductance Lm is connected between inductance Lr and capacitor Cr, transformer T3 includes primary winding N7 and secondary winding N8, the primary winding N7 of transformer T3 is connected in parallel with inductance Lm, and the secondary winding N8 of transformer T3 is connected in parallel with the input terminal of the rectification and filtering unit 323.

[0034] As an example, the rectification and filtering unit 223 includes diode D11, diode D12, diode D13, diode D14, capacitor C0 and resistor R0, the first end of the secondary winding N8 of transformer T3 is connected between the anode of diode D11 and the cathode of diode D13, the second end of the secondary winding N8 of transformer T3 is connected between the anode of diode D12 and the cathode of diode D14, capacitor C0 is connected in parallel with the series branch of diode D12 and diode D14, and capacitor C0 is connected in parallel with resistor R0.

[0035] As an example, when input low voltage and switches S1 and S2 are closed, the capacitor C1 and the capacitor C2 are connected to the circuit to store energy and filter for the voltage regulation circuit, at this time, two-stage control is performed, the control mode of the front stage of the circuit is consistent with the first embodiment, switches S7-S14 in the three-level T-type full-bridge unit 221 are high-frequency switched to input voltage to the resonance unit 222 and the rectification and filtering unit 223 for conversion and filtering.

[0036] As an example, when inputting high voltage, switches S1 and S2 are turned off, and capacitors C1 and C2 are disconnected from the circuit and turned into unipolar control. The three-phase rectifier bridge 11 outputs three line voltages uPN, uPY and uYN via the control tubes Sy1, Sy2 and Sy3, and the input voltage of the DC / DC resonant circuit 22 is also the three line voltages uPN, uPY and uYN, and high-frequency switches S3-S10 feed the voltages uPN, uPY and uYN to the resonant unit 222, which provides soft switching for high-frequency switches. The rectifier filter unit 223 is a full-bridge rectifier filter unit. In each half of the switching period, the energy in the resonant cavity of the resonant unit 222 is completely transferred to the secondary winding, and the capacitor Cr voltage waveform is symmetrical and does not have DC bias.

[0037] As an example, the single-stage circuit controls the size of the energy transferred by the resonant unit 222 to adjust the output voltage or current by adjusting the switching period, and adjusts the size of the resonant current to the P, N and Y end currents by adjusting the duty cycle to achieve three-phase input current power factor correction.

[0038] In the third embodiment of the present application, please refer to Figure 3 The present application also provides a single-stage double-stage switching circuit, Figure 3 is a circuit diagram of the third embodiment of the present application. As Figure 3 shown, in the single-stage double-stage switching circuit, the DC regulating module adopts a DC / DC resonant circuit 22, which includes a three-level T-type full-bridge unit 221, a resonant unit 222 and an output rectifier filter unit 223. It also includes capacitors C1, C2 and C7, and the control tube Sy2 is connected to the bridge arm midpoint of the three-level T-type full-bridge unit 221 through the midpoint of the series branch of the capacitors C1 and C2, and the capacitor C3 is connected to the output end of the AC / DC rectifier circuit, and the rectifier filter unit 223 is connected to the output end of the resonant unit 222. The inductors L1, L2 and L3 are differential mode inductors, and the capacitors C1, C2 and C7 are high-frequency decoupling capacitors.

[0039] As an example, the single-stage circuit input voltage range of the capacitor C1, the capacitor C2 and the capacitor C7 and the inductor L1, the inductor L2 and the inductor L3 cannot be too wide, and normally can only be in the input voltage range of + or - 20%, for example, 304V~456V, and the circuit is further improved in this embodiment. When the input voltage is very low, for example, 266~320Vac, since the inductance of the inductor L1, the inductor L2 and the inductor L3 cannot be too large, the silicon carbide MOS tube is used for the control tube Sy1, the control tube Sy2 and the control tube Sy3 to prevent the circuit from being burned out, and the switch S7~S14 works at a frequency of 200kHz, so the inductance does not need to be too large. At this time, the circuit works in a two-stage rectifier circuit, and the circuit control mode is consistent with the two-stage circuit of the second embodiment. The capacitor C1, the capacitor C2 and the capacitor C7 are energy storage filters. Although the energy transfer efficiency is low, since the input voltage is low, the output power is allowed to be reduced, and the circuit can work normally. When the input voltage is high, for example, 320V~456Vac, the circuit control mode is consistent with the single-stage circuit of the second embodiment, and the capacitor C1 and the capacitor C2 further filter high-frequency noise, and the peak efficiency is greatly improved.

[0040] Further, since there is no Bus electrolytic capacitor in the circuit of the embodiment, when switched to a two-stage circuit, the rectifier circuit only relies on the capacitor C1 and the capacitor C2 to resist interference, and the Bus ripple can be relatively high, and the overshoot of the Bus voltage can also be relatively large. In view of this problem, a non-linear control can be introduced to solve it.

[0041] Specifically, the specific structure of the three-level T-type full-bridge unit 221, the resonance unit 222 and the output rectifier filter unit 223 in the embodiment is the same as that of the related units in the second embodiment, and specific reference can be made to the related description of the second embodiment, which will not be repeated here.

[0042] The application can switch the two-stage rectifier conversion circuit scheme to a single-stage scheme with higher efficiency, or switch the single-stage rectifier conversion circuit scheme to a two-stage scheme with a wider input voltage range, so as to switch the single-stage and two-stage rectifier conversion circuits according to the needs of the input voltage range.

[0043] Although the application has been disclosed as above with the embodiments, it is not intended to limit the application, and anyone with ordinary knowledge in the art can make some changes and modifications without departing from the spirit and scope of the application. Therefore, the protection scope of the application shall be subject to the appended patent claim scope.

Claims

1. A single-stage dual-stage switching circuit, characterized by comprising: The single-stage dual-stage switching circuit comprises: a first inductor, a second inductor, a third inductor, a three-phase rectifier bridge, a first control tube, a second control tube, a third control tube and a direct current regulating module; three input ends of the three-phase rectifier bridge are connected in series with the first inductor, the second inductor and the third inductor respectively, and the three-phase rectifier bridge is connected with an input end of the direct current regulating module through the first control tube, the second control tube and the third control tube respectively, and an output end of the direct current regulating module is connected with a load.

2. The single-stage dual-stage switching circuit of claim 1, wherein, The single-stage dual-stage switching circuit further comprises a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first switch and a second switch, the first capacitor is connected in parallel with a series branch of the third capacitor and the first switch, the second capacitor is connected in parallel with a series branch of the fourth capacitor and the second switch, and a midpoint of a series branch of the second control tube, the first capacitor and the second capacitor is connected.

3. The single-stage dual-stage switching circuit of claim 2, wherein, The direct current regulating module comprises a first direct current regulating unit and a second direct current regulating unit, output ends of the first direct current regulating unit and the second direct current regulating unit are connected in parallel and connected with a load, the first direct current regulating unit is connected in parallel with a series branch of the third capacitor and the first switch, the second direct current regulating unit is connected in parallel with a series branch of the fourth capacitor and the second switch, and the first direct current regulating unit and the second direct current regulating unit are of the same half-bridge resonant circuit topology structure.

4. The single-stage dual-stage switching circuit of claim 3, wherein, The first capacitor and the second capacitor are high-frequency decoupling capacitors, the third capacitor and the fourth capacitor are electrolytic capacitors, and the first inductor, the second inductor and the third inductor are PFC inductors.

5. The single-stage dual-stage switching circuit of claim 1, wherein, The direct current regulating module is a DC / DC resonant circuit, and the DC / DC resonant circuit comprises a three-level T-type full-bridge unit, a resonant unit and an output rectifier filter unit.

6. The single-stage dual-stage switching circuit of claim 5, wherein, The single-stage dual-stage switching circuit further comprises a first capacitor, a second capacitor, a first switch and a second switch, the second control tube is connected with a bridge arm midpoint of the three-level T-type full-bridge unit through a midpoint of a series branch of the first capacitor and the first switch and a midpoint of a series branch of the second capacitor and the second switch, the rectifier filter unit is connected in parallel with an output end of the resonant unit, and the first inductor, the second inductor and the third inductor are PFC inductors.

7. The single-stage dual-stage switching circuit of claim 5, wherein, The single-stage dual-stage switching circuit further comprises a first capacitor, a second capacitor and a third capacitor, the second control tube is connected with a bridge arm midpoint of the three-level T-type full-bridge unit through a midpoint of a series branch of the first capacitor and the second capacitor, the third capacitor is connected in parallel with an output end of the three-phase rectifier bridge, and the rectifier filter unit is connected in parallel with an output end of the resonant unit.

8. A single-stage dual-stage switching circuit according to any one of claims 1 to 7, characterized in that The first switch and the second switch are MOS tubes or relays, and the first control tube, the second control tube and the third control tube are switching tubes.

Images