Bipolar voltage converter

Abstract

The invention relates to the technical field of voltage conversion, and discloses a bipolar voltage converter which comprises a coupling inductor, a capacitor C2, a capacitor C3, a diode branch and a switching tube S1. The coupling inductor comprises a primary winding L1 and a secondary winding L2, the primary winding is electrically connected with the capacitor C1, the diode D1, the output capacitor CO1, the output capacitor CO2, the diode D3 and the diode D4 in sequence through the secondary winding L2, and a loop is formed; during use, firstly, the output capacitor CO1 and the output capacitor CO2 which are connected in series are arranged, and the charging process of the output capacitor CO1 and the output capacitor CO2 is controlled, so that the power supply can supply power to the two loads; in addition, passive clamping is carried out while voltage gain boosting is carried out through a diode D5 and a capacitor C3, and an additional active clamping circuit does not need to be arranged; and finally, the balance influence of parasitic parameters of all components except the internal resistance of the touch diode on the output levels of the two output capacitors can be eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage conversion, and in particular to a bipolar voltage converter. Background Art

[0002] With the development of new energy technologies, the application of solar power generation technology through photovoltaic panels has become more and more widespread. In order to apply the output voltage of photovoltaic panels, it is often necessary to use a voltage converter to boost the output voltage of photovoltaic panels to obtain a higher voltage output.

[0003] Patent No. CN118971605A discloses a soft-switching high-gain DC-DC converter for photovoltaic power generation. However, the circuit in this patent has the following deficiencies: 1: There is only one load connection point in the circuit, and only a single load can be connected; Second: When the load is unbalanced, if the voltage needs to be automatically balanced, an additional active clamping circuit is required, which will make the circuit complex; 3. The parasitic parameters of components in the circuit other than the internal resistance of the diode will affect the balance of the circuit output voltage. Summary of the Invention

[0004] In view of the shortcomings of the background technology, the present invention provides a bipolar voltage converter. The technical problem to be solved is that the existing voltage conversion has only one load connection point, an additional active clamping circuit is required for voltage balancing, and the parasitic parameters of the devices in the circuit will affect the balance of the circuit output voltage.

[0005] To solve the above technical problems, the present invention provides the following technical solutions: a bipolar voltage converter, comprising a coupled inductor, a capacitor C2, a capacitor C3, a diode branch and a switch tube S1; The coupled inductor includes a primary winding L1 and a secondary winding L2. One end of the primary winding L1 is electrically connected to one end of the secondary winding L2, the output end of the switch S1, and one end of the capacitor C3. The other end of the secondary winding L2 is electrically connected to the other end of the primary winding L1 via the capacitor C1, the diode D1, the output capacitor CO1, the output capacitor CO2, the diode D3, and the diode D4 in sequence. The end of the output capacitor CO1 electrically connected to the output capacitor CO2 is electrically connected to the other end of the primary winding L1. The two ends of the capacitor C2 are electrically connected to the other end of the secondary winding L2 and the anode of the diode D4 respectively; The diode branch includes a first connection end, a second connection end, and an intermediate end. The current of the diode branch flows from the first connection end to the second connection end. The first connection end is electrically connected to the cathode of the diode D4, the second connection end is electrically connected to the anode of the diode D1, and the intermediate end is electrically connected to the other end of the capacitor C3. The input end of the switch tube S1 and the other end of the primary winding L1 are electrically connected to the input power supply Vin respectively.

[0006] In some embodiments, the diode branch includes a diode D5 and a diode D2 connected in series, the anode of the diode D5 is the first connection end, the cathode of the diode D5 is the middle end, and the cathode of the diode D2 is the second connection end.

[0007] In some embodiments, the switch tube S1 includes a control terminal. When a high-level control signal is input to the control terminal, the switch tube S1 is turned on. When a low-level control signal is input to the control terminal, the switch tube S1 is turned off.

[0008] In some embodiments, the switch tube S1 is an NMOS tube, the drain of the NMOS tube is the input end of the switch tube S1, the source of the NMOS tube is the output end of the switch tube S1, and the drain of the NMOS tube is the control end of the switch tube S1.

[0009] In a certain embodiment, the cathode of the diode D1 is also electrically connected to the input end of the switch tube Q1 , and the output end of the switch tube Q1 is electrically connected to the anode of the diode D3 through the switch tube Q2 .

[0010] In some implementations, the switch tube Q1 and the switch tube Q2 are both NMOS tubes.

[0011] In some implementations, the switch tube Q1 and the switch tube Q2 are turned on alternately.

[0012] In a certain embodiment, within a working cycle T of the voltage converter, the switch tube S1 is first turned on for a first time t1 and then turned off for a second time t2, where t1+t2=T.

[0013] In a certain embodiment, within a working cycle T of the voltage converter, the voltage converter includes four modes in sequence, as follows: In mode 1, switch S1 is turned on, diodes D1, D3, D4, and D5 are turned off, diode D2 is forward biased, secondary winding L2 is freewheeling through diode D2, and secondary winding L2 and capacitor C3 are connected in series to charge capacitor C1. After the freewheeling of secondary winding L2 ends, mode 1 ends and mode 2 begins. In mode 2, switch S1 continues to conduct, diodes D2, D3, and D5 are off, and diodes D1 and D4 are forward biased. The input power supply Vin connected to switch S1 charges the coil leakage inductance and magnetizing inductance of primary winding L1, increasing the current flowing through secondary winding L2. The input power supply Vin and secondary winding L2 both charge capacitor C2 through diode D4. At the same time, capacitor C1 charges output capacitor C1 through diode D1. When switch S1 stops conducting, mode 2 ends and mode 3 begins. In mode three, the switch S1 is turned off, the diodes D2 and D3 are turned off, the diodes D1, D4, and D5 are forward biased, the primary winding L1 is freewheeling through the diode D5 and capacitor C3, and the secondary winding L2 releases current to discharge. When the release current of the secondary winding L2 is 0, mode three ends and mode four is entered. In mode four, the switch tube S1 continues to be turned off, the diodes D1, D4 and D5 are turned off, the diodes D2 and D3 are forward biased, the capacitor C2 charges the output capacitor CO2 through the primary winding L2 and diode D3 connected in series, and the secondary winding L2 and capacitor C3 charge the capacitor C1 through diode D2. When the switch tube S1 is completely turned off, mode four ends and enters mode one.

[0014] In some implementations, the output capacitor CO1 and the output capacitor CO2 are electrolytic capacitors or CBB capacitors.

[0015] Compared with the prior art, the present invention has the following beneficial effects: First, the present invention provides output capacitors CO1 and CO2 in series, and controls the charging process of output capacitors CO1 and CO2 to enable the present invention to supply power to two loads. Secondly, the present invention uses diode D5 and capacitor C3 to perform passive clamping while increasing the voltage gain, without the need for an additional active clamping circuit; In addition, the circuit of the present invention can eliminate the influence of the parasitic parameters of all components other than the internal resistance of the diode on the balance of the output levels of the two output capacitors. For details, see the analysis content in the embodiment. Finally, by setting the switch tube Q2 and the switch tube Q3, the DC voltage can be converted to the AC voltage, so that the present invention can output DC and AC voltages at the same time on the one hand, and on the other hand, it can also achieve self-balancing of the DC power of the DC load and the AC power of the AC load, and can perform power transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A first implementation circuit diagram of the present invention in an embodiment; Figure 2A second implementation circuit diagram of the present invention in an embodiment; Figure 3 for Figure 2 Schematic diagram of current flow when the circuit shown works in mode 1; Figure 4 for Figure 2 Schematic diagram of current flow when the circuit shown works in mode 2; Figure 5 for Figure 2 Schematic diagram of current flow when the circuit shown works in mode three; Figure 6 for Figure 2 Schematic diagram of current flow when the circuit shown works in mode 4; Figure 7 for Figure 2 The waveform of the voltage on output capacitor CO1 and output capacitor CO2 during circuit simulation; Figure 8 for Figure 2 Waveform diagram of bipolar output voltage during circuit simulation. DETAILED DESCRIPTION

[0017] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0018] like Figure 1 As shown, a bipolar voltage converter provided by this embodiment includes a coupled inductor, a capacitor C2, a capacitor C3, a diode branch 1 and a switch tube S1; The coupled inductor includes a primary winding L1 and a secondary winding L2. One end of the primary winding L1 is electrically connected to one end of the secondary winding L2, the output end of the switch S1, and one end of the capacitor C3. The other end of the secondary winding L2 is electrically connected to the other end of the primary winding L1 through capacitor C1, diode D1, output capacitor CO1, output capacitor CO2, diode D3, and diode D4 in sequence. The end of the output capacitor CO1 electrically connected to the output capacitor CO2 is electrically connected to the other end of the primary winding L1. The two ends of the capacitor C2 are electrically connected to the other end of the secondary winding L2 and the anode of the diode D4 respectively; Diode branch 1 includes a first connection end, a second connection end, and an intermediate end. The current of the diode branch flows from the first connection end to the second connection end. The first connection end is electrically connected to the cathode of diode D4, the second connection end is electrically connected to the anode of diode D1, and the intermediate end is electrically connected to the other end of capacitor C3. The input end of the switch tube S1 and the other end of the primary winding L1 are electrically connected to the input power supply Vin respectively.

[0019] Specifically, in this embodiment, Figure 1 As shown, the diode branch 1 includes a diode D5 and a diode D2 connected in series, the anode of the diode D5 is the first connection end, the cathode of the diode D5 is the middle end, and the cathode of the diode D2 is the second connection end.

[0020] Specifically, in this embodiment, the switch tube S1 includes a control terminal. When a high-level control signal is input to the control terminal, the switch tube S1 is turned on. When a low-level control signal is input to the control terminal, the switch tube S1 is turned off. The switch tube S1 is an NMOS tube, the drain of the NMOS tube is the input end of the switch tube S1 , the source of the NMOS tube is the output end of the switch tube S1 , and the drain of the NMOS tube is the control end of the switch tube S1 .

[0021] In addition, in this embodiment, the on-off control process of the switch tube S1 within one working cycle T of the voltage converter is as follows: The switch tube S1 is first turned on for a first time t1 and then turned off for a second time t2, and t1+t2=T.

[0022] In some implementations, the switch S1 may also be an IGBT type device, which is turned on when a high-level control signal is input to the control terminal, and is turned off when a low-level control signal is input to the control terminal.

[0023] In this embodiment, Figure 2 This embodiment also provides a bipolar voltage converter with another structure. Figure 2 and Figure 1 The difference is that the cathode of the diode D1 is also electrically connected to the input end of the switch tube Q1, and the output end of the switch tube Q1 is electrically connected to the anode of the diode D3 through the switch tube Q2.

[0024] Specifically, in Figure 2 In the embodiment, the switch tube Q1 and the switch tube Q2 are both NMOS tubes; and the switch tube Q1 and the switch tube Q2 are turned on alternately, that is, when the switch tube Q1 is turned on, the switch tube Q2 is turned off, and when the switch tube Q1 is turned off, the switch tube Q2 is turned on.

[0025] exist Figure 2 By controlling the on / off of the switch tubes Q1 and Q2, the output end of the switch tube 1 and the end electrically connected to the output capacitor CO1 and the output capacitor CO2 can output an AC voltage, so that the entire circuit can output both a DC voltage and an AC voltage.

[0026] Specifically, in this embodiment, the output capacitor CO1 and the output capacitor CO2 are electrolytic capacitors or CBB capacitors.

[0027] It should be noted that Figure 1The resistors R1 and R2 in the figure represent loads.

[0028] right Figure 2 The working process of the circuit shown is analyzed as follows: During one working cycle T of the voltage converter, the voltage converter includes four modes in sequence, as follows: In mode 1, the switch tube S1 is turned on, the diodes D1, D3, D4 and D5 are turned off, the diode D2 is forward biased, the secondary winding L2 is freewheeling through the diode D2, the secondary winding L2 and the capacitor C3 are connected in series to charge the capacitor C1, and after the freewheeling of the secondary winding L2 ends, mode 1 ends and enters mode 2; Figure 2 The current flow direction of the circuit in mode 1 is as follows Figure 3 As shown; In mode 2, the switch S1 continues to conduct, the diodes D2, D3, and D5 are turned off, and the diodes D1 and D4 are forward biased. The input power supply Vin connected to the switch S1 charges the coil leakage inductance and magnetizing inductance of the primary winding L1, and the current flowing through the secondary winding L2 increases. The input power supply Vin and the secondary winding L2 both charge the capacitor C2 through the diode D4. At the same time, the capacitor C1 charges the output capacitor C1 through the diode D1. When the switch S1 stops conducting, mode 2 ends and enters mode 3. Figure 2 The current flow direction of the circuit in mode 2 is as follows Figure 4 As shown; In mode three, the switch tube S1 is turned off, the diodes D2 and D3 are turned off, the diodes D1, D4 and D5 are forward biased, the primary winding L1 is freewheeling through the diode D5 and the capacitor C3, and the secondary winding L2 releases the current to discharge. When the release current of the secondary winding L2 is 0, mode three ends and mode four is connected; Figure 2 The current flow direction of the circuit in mode 3 is as follows Figure 5 shown In mode 4, the switch tube S1 continues to be turned off, the diodes D1, D4 and D5 are turned off, the diodes D2 and D3 are forward biased, the capacitor C2 charges the output capacitor CO2 through the primary winding L2 and diode D3 in series, and the secondary winding L2 and capacitor C3 charge the capacitor C1 through diode D2. When the switch tube S1 is completely turned off, mode 4 ends and enters mode 1. Figure 2 The current flow direction of the circuit in mode 4 is as follows Figure 6 shown.

[0029] In addition, Figure 3-Figure 6 The circuit status in the figure is explained, where the direction of the arrow indicates the direction of current flow, and the electronic components in the gray line state are in a non-working state.

[0030] Combining the above circuit in four modes, the following formula can be obtained: VC1=(D+N*D*K)*Vin / (1-D); VC2=Vin+N*K*Vin; VCO1=(1+N*K)*Vin / (1-D); VCO2=(1+N*K)*Vin / (1-D); MCCM=2*(1+N*K) / (1-D).

[0031] For the above five formulas: VC1, VC2, VCO1 and VCO2 are the terminal voltages of capacitor C1, capacitor C2, output capacitor CO1 and output capacitor CO2 respectively, MCCM is the voltage gain of the circuit, D is the on-time duty cycle of the switch tube S1 in one cycle, N is the turns ratio of the primary winding L1 and the secondary winding L2, and K is the coupling coefficient of the primary winding L1 and the secondary winding L2.

[0032] From the above five formulas we can get: .

[0033] For this formula: is the voltage difference between the load resistor R1 and the load resistor R2, I O1 and I O2 are the current values ​​flowing through R1 and R2 respectively, R d is the internal resistance of the diode, V d is the diode voltage drop. Assuming that all diodes in the converter are consistent, it can be obtained from this formula that the circuit of the present invention eliminates the influence of the parasitic parameters of all components except the internal resistance of the diode on the bipolar voltage balance, and has a strong ability to resist the influence of parasitic parameters.

[0034] right Figure 2 The circuit shown in the figure is simulated, and the simulation diagrams are as follows Figure 7 and Figure 8 As shown; exist Figure 7 The upper waveform is the voltage on the output capacitor CO1, and the lower waveform is the voltage on the output capacitor CO2. Figure 7 It can be seen that the voltage fluctuation on the output capacitor CO1 is about 0.1V, and the voltage fluctuation on the output capacitor CO2 is about 0.09V; exist Figure 8 The output voltage of the present invention, i.e., the sum of the voltage on the output capacitor CO1 and the voltage on the output capacitor CO2, is stable at about 380V, and the voltage fluctuation is 0.08V; Combine Figure 7 and Figure 8 According to the simulation results, the voltage difference between the voltage on the output capacitor CO1 and the voltage on the output capacitor CO2 of the present invention is very small, and the connected output voltage has an extremely low output voltage ripple.

[0035] In view of the above, the present invention has the following advantages in practical use: 1. The present invention can supply power to two loads by providing an output capacitor CO1 and an output capacitor CO2 connected in series and controlling the charging process of the output capacitor CO1 and the output capacitor CO2; Second: The present invention uses diode D5 and capacitor C3 to increase voltage gain while also performing passive clamping, eliminating the need for an additional active clamping circuit. 3. The circuit of the present invention can eliminate the influence of parasitic parameters of all components except the internal resistance of the diode on the balance of the output levels of the two output capacitors; Fourth: By providing the switch tubes Q2 and Q3, DC voltage can be converted to AC voltage, thereby enabling the present invention to simultaneously output DC and AC voltages, and also to achieve self-balancing of the DC power of the DC load and the AC power of the AC load, thereby enabling power transfer; 5. When the switch tube S1 is turned off, the input power supply Vin can be separated from the subsequent circuit, reducing the common-mode and differential-mode interference of the input power supply Vin from being transmitted to the subsequent circuit.

[0036] The above description is for inspiration. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical concept of this invention. The technical scope of this invention is not limited to the content of the specification, but must be determined according to the scope of the claims.

Claims

1. A bipolar voltage converter, characterized in that: It includes a coupled inductor, a capacitor C2, a capacitor C3, a diode branch and a switch tube S1; The coupled inductor includes a primary winding L1 and a secondary winding L2. One end of the primary winding L1 is electrically connected to one end of the secondary winding L2, the output end of the switch S1, and one end of the capacitor C3. The other end of the secondary winding L2 is electrically connected to the other end of the primary winding L1 via the capacitor C1, the diode D1, the output capacitor CO1, the output capacitor CO2, the diode D3, and the diode D4 in sequence. The end of the output capacitor CO1 electrically connected to the output capacitor CO2 is electrically connected to the other end of the primary winding L1. The two ends of the capacitor C2 are electrically connected to the other end of the secondary winding L2 and the anode of the diode D4 respectively; The diode branch includes a first connection end, a second connection end, and an intermediate end. The current of the diode branch flows from the first connection end to the second connection end. The first connection end is electrically connected to the cathode of the diode D4, the second connection end is electrically connected to the anode of the diode D1, and the intermediate end is electrically connected to the other end of the capacitor C3. The input end of the switch tube S1 and the other end of the primary winding L1 are electrically connected to the input power supply Vin respectively.

2. A bipolar voltage converter according to claim 1, characterized in that: The diode branch includes a diode D5 and a diode D2 connected in series, the anode of the diode D5 is the first connection end, the cathode of the diode D5 is the middle end, and the cathode of the diode D2 is the second connection end.

3. The bipolar voltage converter according to claim 1, wherein: The switch tube S1 includes a control end. When a high-level control signal is input to the control end, the switch tube S1 is turned on. When a low-level control signal is input to the control end, the switch tube S1 is turned off.

4. The bipolar voltage converter according to claim 3, characterized in that: The switch tube S1 is an NMOS tube, the drain of the NMOS tube is the input end of the switch tube S1 , the source of the NMOS tube is the output end of the switch tube S1 , and the drain of the NMOS tube is the control end of the switch tube S1 .

5. The bipolar voltage converter according to claim 1, wherein: The cathode of the diode D1 is also electrically connected to the input end of the switch tube Q1 , and the output end of the switch tube Q1 is electrically connected to the anode of the diode D3 through the switch tube Q2 .

6. The bipolar voltage converter according to claim 5, characterized in that: The switch tube Q1 and the switch tube Q2 are both NMOS tubes.

7. The bipolar voltage converter according to claim 5, characterized in that: The switch tube Q1 and the switch tube Q2 are turned on alternately.

8. A bipolar voltage converter according to any one of claims 1 to 7, characterized in that: In a working cycle T of the voltage converter, the switch tube S1 is first turned on for a first time t1 and then turned off for a second time t2, where t1+t2=T.

9. A bipolar voltage converter according to any one of claims 1 to 7, characterized in that: During one working cycle T of the voltage converter, the voltage converter includes four modes in sequence, as follows: In mode 1, switch S1 is turned on, diodes D1, D3, D4, and D5 are turned off, diode D2 is forward biased, secondary winding L2 is freewheeling through diode D2, and secondary winding L2 and capacitor C3 are connected in series to charge capacitor C1. After the freewheeling of secondary winding L2 ends, mode 1 ends and mode 2 begins. In mode 2, switch S1 continues to conduct, diodes D2, D3, and D5 are off, and diodes D1 and D4 are forward biased. The input power supply Vin connected to switch S1 charges the coil leakage inductance and magnetizing inductance of primary winding L1, increasing the current flowing through secondary winding L2. The input power supply Vin and secondary winding L2 both charge capacitor C2 through diode D4. At the same time, capacitor C1 charges output capacitor C1 through diode D1. When switch S1 stops conducting, mode 2 ends and mode 3 begins. In mode three, the switch S1 is turned off, the diodes D2 and D3 are turned off, the diodes D1, D4, and D5 are forward biased, the primary winding L1 is freewheeling through the diode D5 and capacitor C3, and the secondary winding L2 releases current to discharge. When the release current of the secondary winding L2 is 0, mode three ends and mode four is entered. In mode four, the switch tube S1 continues to be turned off, the diodes D1, D4 and D5 are turned off, the diodes D2 and D3 are forward biased, the capacitor C2 charges the output capacitor CO2 through the primary winding L2 and diode D3 connected in series, and the secondary winding L2 and capacitor C3 charge the capacitor C1 through diode D2. When the switch tube S1 is completely turned off, mode four ends and enters mode one.

10. The bipolar voltage converter according to claim 1, characterized in that: The output capacitor CO1 and the output capacitor CO2 are electrolytic capacitors or CBB capacitors.

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