CN203911753U - Zero-voltage switch-off interleaved parallel DC/DC converter - Google Patents

Abstract

The utility model relates to a zero-voltage switch-off interleaved parallel DC/DC converter. The zero-voltage switch-off interleaved parallel DC/DC converter comprises a first inductor L1, a second inductor L2, a first power switch tube S1, a second power switch tube S2, an output diode D0 and a filtering capacitor C0; one end of the first inductor L1 and one end of the second inductor L2 are both connected with the positive pole of a power source Uin; the other end of the first inductor L1 is connected with the drain of the first power switch tube S1; the other end of the second inductor L2 is connected with the drain of the second power switch tube S2; and the source of the first power switch tube S1 and the source of the second power switch tube S2 are connected with the negative pole of the power source Uin. According to the zero-voltage switch-off interleaved parallel DC/DC converter provided by the utility model, the zero-voltage switch-off of the switch tubes can be realized, and therefore, switching loss of the switch tubes can be decreased effectively, and work efficiency is high.

Description

Zero-Voltage Turn-Off Interleaved Parallel DC/DC Converter

technical field

The utility model relates to a DC/DC converter, in particular to a zero-voltage turn-off interleaved parallel DC/DC converter.

Background technique

In the prior art, a basic step-up (Boost) interleaved parallel converter includes: two inductors, two power switch tubes, and two output diodes. Among them, the input terminal of the first inductor and the input terminal of the second inductor are connected to the positive pole of the input power supply, the output terminal is connected to the anode of the first output diode, and the cathode of the first diode is connected to the cathode of the second diode together. The positive pole of the output terminal of the converter; the drain of the first power switch tube is connected between the first inductor and the anode of the first diode, and the source of the first power switch tube is connected to the negative pole of the converter; the output terminal of the second inductor is connected to the first power switch tube The anodes of the two output diodes are connected between the second inductor and the anodes of the second diode to the drain of the second power switch tube, and the source of the second power switch tube is connected to the negative pole of the converter. The output voltage gain of this basic step-up interleaved parallel converter is small, and the voltage stress of the power switch tube and diode is the output voltage, so the loss is also large. In addition, both the switch tube and the diode work in the hard switching mode, so the switching loss and the reverse recovery loss of the diode are relatively large. In recent years, some circuit topologies with both high-gain boost and soft switching capabilities have emerged, mainly by means of coupled inductors and active clamping. This method increases the gain of the original converter on the one hand, and on the other hand The soft switching operation is also realized, but due to the need to consider the problem of multi-phase current sharing, the circuit control scheme is more complicated, and the cost is higher due to more components.

Contents of the invention

Aiming at the deficiencies of the prior art, in order to solve the problems of reduced energy conversion efficiency, too many switching devices, and large voltage stress of switching tubes and diodes, etc., when the existing converter is applied in a high-boost application. The utility model provides a zero-voltage turn-off interleaved parallel DC/DC converter. The switching tubes all realize zero-voltage turn-off, which can effectively reduce the switching loss of the switching tubes, and the working efficiency is high.

The technical solution adopted by the utility model is: zero-voltage turn-off interleaved parallel DC/DC converter, including the first inductance L ₁ , the second inductance L ₂ , the first power switch tube S ₁ , and the second power switch tube S ₂ , output diode D ₀ , filter capacitor C ₀ ,

One end of the first inductance _L1 and one end of the second inductance _L2 are both connected to the positive pole of the power supply U _in , the other end of the first inductance _L1 is connected to the drain of the first power switch _S1 , and the other end of the second inductance _L2 is connected to The drain of the second power switch _S2 , the source of the first power switch _S1 , and the source of the second power switch _S2 are connected to the negative pole of the power supply U _in . The other end of the first inductance _L1 and the other end of the second inductance _L2 are respectively connected to a gain circuit composed of a plurality of voltage doubler units connected in series, the gain circuit is connected to an auxiliary unit, and the auxiliary unit is connected to the anode of the output diode _D0 , the filter capacitor One end of C ₀ , the cathode of the output diode D ₀ is connected to one end of the filter capacitor C ₀ , and the other end of the filter capacitor C ₀ is connected to the negative pole of the power supply U _in .

The gain circuit includes the nth voltage doubler unit, the n-1th voltage doubler unit, the n-2th voltage doubler unit, ... the first voltage doubler unit, and the other end of the first inductor L1 is connected to the nth doubler unit. The first interface of the pressure unit, the other end of the second inductor L2 is connected to the second interface of the nth voltage doubler unit, and the third interface and the fourth interface of the nth voltage doubler unit are distributed to the n-1th voltage doubler The first interface and the second interface of the unit, the third interface and the fourth interface of the n-1th voltage doubler unit are distributed to the first interface and the second interface of the n-2th voltage doubler unit , and so on until the third interface and the fourth interface of the second voltage doubler unit are connected to the first interface and the second interface of the first voltage doubler unit.

The auxiliary unit includes an auxiliary capacitor C _a1 , a first diode D _a1 , and a second diode D _a2 , one end of the auxiliary capacitor C _a1 is connected to the gain circuit, and the other end of the auxiliary capacitor C _a1 is connected to the end of the first diode D _a1 The cathode, the anode of the second diode D _a2 , the anode of the first diode D _a1 is connected to the gain circuit, the anode of the output diode _D0 , the cathode of the second diode D _a2 is connected to the cathode of the output diode _D0 , filter One end of capacitor _C0 . The zero-voltage turn-off of all switching tubes can be realized through the auxiliary unit.

The source of the first power switch _S1 and the gate of the second power switch _S2 are respectively connected to their respective controllers, and the driving phases of the first power switch _S1 and the second power switch _S2 are different from each other 180°.

Each voltage doubling unit includes a diode D and a capacitor C, one end of the capacitor C is connected to a cathode of the diode, and each voltage doubling unit includes four interfaces.

The utility model is a zero-voltage turn-off interleaved parallel DC/DC converter, and the beneficial effects are as follows:

1) The high-gain output of the converter can be achieved by using the voltage doubler unit, and the input-output gain ratio can be adjusted by using the number of voltage doubler units; one voltage doubler unit can increase the basic gain by 1 times, that is to say, it contains n voltage doubler units The unit's circuit has a gain ratio that is (n+1) times that of the basic boost converter.

2) Compared with the existing solutions, the utility model has a simple circuit, no coupling inductance, small EMI, no transformer, and lower voltage stress of the switching device.

3) All switching tubes have achieved zero-voltage turn-off, which can effectively reduce the switching loss of the switching tubes, and is especially effective for applications using IGBTs, and the converter has a high working efficiency.

Description of drawings

Fig. 1 is a circuit diagram of a zero voltage turn-off interleaved parallel DC/DC converter including a voltage doubler unit.

Fig. 2 is a circuit diagram of a zero voltage turn-off interleaved parallel DC/DC converter including n voltage doubler units.

Figure 3 is a circuit diagram of the voltage doubler unit.

Detailed ways

As shown in Figures 1 to 3, the zero-voltage turn-off interleaved parallel DC/DC converter includes a first inductor L ₁ , a second inductor L ₂ , a first power switch S ₁ , and a second power switch S ₂ , output diode D ₀ , and filter capacitor C ₀ , one end of the first inductor L ₁ and one end of the second inductor L ₂ are connected to the positive pole of the power supply U _in , and the other end of the first inductor L ₁ is connected to the first power switch S ₁ Drain, the other end of the second inductor _L2 is connected to the drain of the second power switch _S2 , the source of the first power switch _S1 and the source of the second power switch _S2 are connected to the negative pole of the power supply U _in . The source of the first power switch _S1 and the gate of the second power switch _S2 are respectively connected to their respective controllers, and the driving phases of the first power switch _S1 and the second power switch _S2 are different from each other 180°.

The other end of the first inductance _L1 and the other end of the second inductance _L2 are respectively connected to a gain circuit composed of a plurality of voltage doubler units connected in series, the gain circuit is connected to an auxiliary unit, and the auxiliary unit is connected to the anode of the output diode _D0 , the filter capacitor One end of C ₀ , the cathode of the output diode D ₀ is connected to one end of the filter capacitor C ₀ , and the other end of the filter capacitor C ₀ is connected to the negative pole of the power supply U _in . The gain circuit includes the nth voltage doubler unit, the n-1th voltage doubler unit, the n-2th voltage doubler unit, ... the first voltage doubler unit, and the other end of the first inductor L1 is connected to the nth doubler unit. The first interface of the pressure unit, the other end of the second inductor L2 is connected to the second interface of the nth voltage doubler unit, and the third interface and the fourth interface of the nth voltage doubler unit are distributed to the n-1th voltage doubler The first interface and the second interface of the unit, the third interface and the fourth interface of the n-1th voltage doubler unit are distributed to the first interface and the second interface of the n-2th voltage doubler unit , and so on until the third interface and the fourth interface of the second voltage doubler unit are connected to the first interface and the second interface of the first voltage doubler unit. n is a natural number, the value range is . The auxiliary unit includes an auxiliary capacitor C _a1 , a first diode D _a1 , and a second diode D _a2 , one end of the auxiliary capacitor C _a1 is connected to the gain circuit, and the other end of the auxiliary capacitor C _a1 is connected to the end of the first diode D _a1 The cathode, the anode of the second diode D _a2 , the anode of the first diode D _a1 is connected to the gain circuit, the anode of the output diode _D0 , the cathode of the second diode D _a2 is connected to the cathode of the output diode _D0 , filter One end of capacitor _C0 .

Each voltage doubler unit includes a diode D and a capacitor C, one end of the capacitor C is connected to the cathode of the diode, and each voltage doubler unit includes four interfaces, as shown in FIG. 3 , interface ①, interface ②, interface ③, and interface ④.

According to the different switch switching states of the converter, it can be divided into four working processes, which are: the process of the first power switch tube _S1 being turned on to off, the process of the first power switch tube _S1 from being turned off to on; the second The process from turning on to turning off the power switch tube _S2 , and the process from turning off to turning on the second power switch tube _S2 . details as follows:

1) The process from turning on to turning off the first power switch tube _S1 : before the first power switch tube _S1 is turned off, both the first power switch tube _S1 and the second power switch tube _S2 are in the conduction state, The output diode D ₀ , diode D ₁ , first diode D _a1 , and second diode D _a2 are all in the off state, the voltage at the terminal of the auxiliary capacitor C _a1 is u _o /2, and the terminal of the capacitor C ₁ on the voltage doubler unit The voltage is u _o /2. When the first power switch tube S ₁ is turned off, the first inductor L ₁ charges the auxiliary capacitor C a1 through the capacitor C ₁ on the voltage doubler unit, the first diode D _a1 and the second power switch tube _{S 2} , the first The rising speed of the voltage at the terminal of the power switch tube _S1 is limited by the action of the auxiliary capacitor C _a1 , and its rising speed is consistent with the rising speed of the voltage at the terminal of the auxiliary capacitor C _a1 , so the first power switching tube _S1 realizes zero-voltage turn-off, and the The process continues until the voltage at the terminal of the auxiliary capacitor C _a1 rises to the output voltage u _o and ends. Then the auxiliary first diode D _a1 is turned off, the output diode D ₀ is turned on, and the first inductor L ₁ supplies power to the filter capacitor C ₀ and the load through the capacitor C ₁ on the voltage doubler unit and the output diode D ₀ .

2) The process from turning off the first power switch _S1 to turning on: before the first power switch _S1 is turned on, the second power switch _S2 is in the conduction state, and the output diode _D0 is in the conduction state, The diode D ₁ , the first diode D _a1 , and the second diode D _a2 are all in an off state, the voltage at the terminal of the auxiliary capacitor C _a1 is u _o , and the voltage at the terminal of the capacitor C ₁ on the voltage doubler unit is u _o /2. When the first power switch _S1 is turned on, the output diode _D0 is turned off, the capacitor _C1 on the voltage doubler unit stops discharging, and the input power charges the first inductor _L1 through the first power switch _S1 .

3) The process from turning on to turning off the second power switch tube _S2 : before the second power switch tube _S2 is turned off, both the first power switch tube _S1 and the second power switch tube _S2 are in the conduction state, The output diode D ₀ , diode D ₁ , first diode D _a1 , and second diode D _a2 are all in the off state, the voltage at the terminal of the auxiliary capacitor C _a1 is u _o , and the voltage at the terminal of the capacitor C ₁ on the voltage doubler unit is u _o /2. When the second power switch tube _S2 is turned off, the inductance _L2 and the auxiliary capacitor C _a1 supply power to the output filter capacitor _C0 and the load through the diode D _a2 , and the voltage rise speed of the second power switch tube _S2 terminal is equal to that of the auxiliary capacitor C _a1 is limited under the action of the auxiliary capacitor C a1, and its rising speed is consistent with the falling speed of the terminal voltage of the capacitor C _a1 , so the second power switch _S2 also realizes zero-voltage turn-off, and this process continues until the voltage of the auxiliary capacitor C _a1 terminal drops to u _o / 2 over. Then the auxiliary diode D _a2 is turned off, the diode _D1 is turned on, and the second inductor _L2 charges the capacitor _C1 on the voltage doubler unit through the first power switch _S1 .

4) The process from turning off the second power switch _S2 to turning on: before the second power switch _S2 is turned on, the first power switch _S1 is in the conduction state, the diode D1 is in the conduction state, and the diode _D1 is in the conduction state. D ₀ , D _a1 , and D _a2 are all in the off state, the voltage at the terminal of the auxiliary capacitor C _a1 is u _o /2, and the voltage at the terminal of the capacitor C ₁ on the voltage doubler unit is u _o /2. When the second power switch _S2 is turned on, the diode _D1 is turned off, the capacitor _C1 on the voltage doubler unit stops charging, and the input power charges the second inductor _L2 through the second power switch _S2 .

The first power switch tube S ₁ and the second power switch tube S ₂ select switching devices with different voltage stresses according to the difference in the DC bus voltage required in the system. It should be noted that the voltage stress of the first power switch S ₁ and the second power switch S ₂ is only half of that of the high-voltage DC bus. The first power switch tube S ₁ and the second power switch tube S ₂ are turned on and off under the control of the controller. The above-mentioned 2 times high gain boost circuit is controlled by the controller to control the first power switch tube S ₁ and the second power switch tube S 1 . The duty cycle of the switching tube _S2 has a phase difference of 180° between each phase. The duty cycle of each phase is determined according to the relationship between input and output.

The utility model is a zero-voltage turn-off interleaved parallel DC/DC converter, which has a gain ratio of 2 times compared with a basic interleaved parallel Boost converter, and all switch tubes realize zero-voltage turn-off. The input end of the converter is connected to a voltage supply module, such as a photovoltaic cell, a fuel cell, etc., and the output voltage is a controllable high-voltage direct current. To sum up, the circuit topology is simple, the boost capability is strong, and the switching loss is low, and it is suitable for some occasions where the input and output voltage differences are large.

Claims (6)

1. no-voltage is turn-offed staggered-parallel-type DC/DC converter, comprises the first inductance L ₁, the second inductance L ₂, the first power switch tube S ₁, the second power switch tube S ₂, output diode D ₀, filter capacitor C ₀, it is characterized in that,

Described the first inductance L ₁one end, the second inductance L ₂one end all connects power supply U _inpositive pole, the first inductance L ₁the other end connects the first power switch tube S ₁drain electrode, the second inductance L ₂the other end connects the second power switch tube S ₂drain electrode, the first power switch tube S ₁source electrode, the second power switch tube S ₂source electrode connect power supply U _innegative pole;

Described the first inductance L ₁the other end, the second inductance L ₂the other end connects respectively a plurality of voltage doubling units gain circuitry in series, and described gain circuitry connects auxiliary unit, and auxiliary unit connects output diode D ₀anode, filter capacitor C ₀one end, output diode D ₀negative electrode connect filter capacitor C ₀one end, filter capacitor C ₀the other end connects power supply U _innegative pole.

2. no-voltage is turn-offed staggered-parallel-type DC/DC converter according to claim 1, it is characterized in that, described gain circuitry comprises n voltage doubling unit, n-1 voltage doubling unit, n-2 voltage doubling unit, the 1st voltage doubling unit, first inductance L 1 other end connects the first interface of n voltage doubling unit, second inductance L 2 other ends connect the second interface of n voltage doubling unit, the 3rd interface of n voltage doubling unit and the 4th interface distribute and connect first interface and second interface of n-1 voltage doubling unit, the 3rd interface of n-1 voltage doubling unit and the 4th interface distribute and connect first interface and second interface of n-2 voltage doubling unit, the like until the 3rd interface of the 2nd voltage doubling unit and the 4th interface distribute, connect first interface and second interface of the 1st voltage doubling unit.

3. no-voltage is turn-offed staggered-parallel-type DC/DC converter according to claim 1, it is characterized in that, described auxiliary unit comprises auxiliary capacitor C _a1, the first diode D _a1, the second diode D _a2, auxiliary capacitor C _a1one end connects gain circuitry, auxiliary capacitor C _a1the other end connects the first diode D _a1negative electrode, the second diode D _a2anode, the first diode D _a1anodic bonding gain circuitry, output diode D ₀anode, the second diode D _a2negative electrode connect output diode D ₀negative electrode, filter capacitor C ₀one end.

4. no-voltage is turn-offed staggered-parallel-type DC/DC converter according to claim 1, it is characterized in that described the first power switch tube S ₁source electrode, the second power switch tube S ₂grid connect respectively each self-controller, the first power switch tube S ₁, the second power switch tube S ₂driving phase place between differ 180 °.

5. no-voltage is turn-offed staggered-parallel-type DC/DC converter according to claim 2, it is characterized in that, each voltage doubling unit comprises diode D, capacitor C, and capacitor C one end connects diode cathode, and each voltage doubling unit comprises four interfaces.

6. no-voltage is turn-offed staggered-parallel-type DC/DC converter according to claim 1, it is characterized in that described power supply U _infor photovoltaic cell or fuel cell.