CN104852571A - Zero-voltage-transition power supply-capacitor series connection type DC converter and working method thereof - Google Patents

Abstract

The invention discloses a zero-voltage conversion power supply-capacitor series DC converter and its working method. The zero-voltage conversion power supply-capacitor series DC converter includes a power circuit and a main power circuit; The connected DC power supply S ₁ , the central capacitor C _cen and the DC power supply S ₂ , the power supply circuit supplies power to the subsequent circuit or load; the main power circuit includes a first main power circuit and a second main power circuit, the The first main power circuit is connected in parallel between the common point of the central capacitor C _cen and the DC power source S ₂ and the positive pole of the DC power source S ₁ ; the second main power circuit is connected in parallel between the common point of the central capacitor C _cen and the DC power source S ₁ point and the negative pole of the DC power supply _S2 . The invention greatly reduces the switching loss of the main switch tube and the main diode of the power supply-capacitor series DC converter, and greatly improves the conversion efficiency of the converter.

Description

Zero-voltage switching power supply-capacitor series DC converter and its working method

technical field

The invention relates to a soft switching circuit, in particular to a zero-voltage conversion power supply-capacitor series DC converter and a working method thereof.

Background technique

Since modern times, with the continuous consumption of fossil energy, human beings are facing an unprecedented energy crisis. Photovoltaic power generation technology has been widely used because it provides a steady stream of renewable electricity for human society without consuming any fossil energy.

As the core component of the entire photovoltaic power generation system, photovoltaic inverters are crucial to their operating efficiency and performance. Currently widely used distributed non-isolated photovoltaic grid-connected inverters widely adopt a two-stage topology, and the first-stage DC-DC conversion circuit mostly adopts a boost converter with a zero-voltage conversion circuit. The zero-voltage transfer circuit significantly reduces the switching loss of the main switching tube and the reverse recovery loss of the main diode, and has been widely used.

However, the traditional boost converter circuit with zero voltage conversion circuit has the following problems:

(1) The voltage stress of the switch tube and diode is the DC output voltage value, and the voltage stress is relatively large;

(2) When hardware engineers select semiconductor devices, they must choose semiconductor devices with a withstand voltage higher than the DC output voltage value, resulting in high costs;

(3) In addition, under the condition of high step-up ratio, the current stress of the main switch tube and the main diode is relatively large, resulting in a decrease in conversion efficiency.

Contents of the invention

A zero-voltage conversion power supply-capacitor series DC converter and its working method proposed by the present invention, wherein the main power circuit of the zero-voltage conversion power supply-capacitor series DC converter is divided into a first main power circuit and a second main power circuit. The power circuit respectively realizes the energy transfer between the DC power supply S1 and the central capacitor C _cen , the DC power source S ₂ and the central capacitor C _cen , and the present invention realizes the zero _- voltage turn-on and zero-voltage turn-off of the main switching tube, and the main diode The zero-voltage turn-on and zero-voltage turn-off, and the auxiliary switch tube and auxiliary diode hardly increase the loss of the circuit.

To achieve the above object, the present invention adopts the following technical solutions:

A zero-voltage conversion power supply-capacitor series DC converter, comprising: a power supply circuit and a main power circuit;

The power supply circuit includes a DC power supply S ₁ , a central capacitor C _cen and a DC power supply S ₂ sequentially connected in series, and the power supply circuit supplies power to subsequent circuits or loads;

The main power circuit includes a first main power circuit and a second main power circuit, and the first main power circuit is connected in parallel between the central capacitor C _cen and the common point of the DC power supply S ₂ and the positive pole of the DC power supply S ₁ ; The second main power circuit is connected in parallel between the common point of the central capacitor C _cen and the DC power source S ₁ and the negative pole of the DC power source S ₂ .

The first main power circuit includes:

The main switching tube T _1u and the main inductor L _Fu , the collector or drain of the main switching tube T _1u is connected to the positive pole of the DC power supply S ₁ , the emitter or source of the main switching tube T _1u is connected to the main inductor L _Fu One end is connected, and the other end of the main inductor L _Fu is connected to the negative pole _of the DC power supply S1;

The common point of the main switching tube T _1u and the main inductor L _Fu is connected to the cathode of the main diode D _Fu , and the anode of the main diode D _Fu is connected to the common point of the positive pole of the DC power supply S ₂ and the central capacitor C _cen ;

The anode of the DC power supply S ₁ is connected to the collector or drain of the auxiliary switching tube T _2u , the emitter or source of the auxiliary switching tube T _2u is connected to one end of the resonant inductance L _ru , and the other end of the resonant inductance L _ru is connected to the main The common point of the switching tube T _1u and the main inductance L _Fu ;

The common point of the resonant inductance L _ru and the auxiliary switching tube T _2u is connected to the cathode of the auxiliary diode D _1u , the anode of the auxiliary diode D _1u is connected to the cathode of the auxiliary diode D _2u , and the anode of the auxiliary diode D _2u is connected to the DC power supply S ₂ The common point of the positive electrode and the central capacitor C _cen ;

The cathode of the main diode D _Fu is connected to one end of the capacitor C _Bu , and the other end of the capacitor C _Bu is connected to the common point of the auxiliary diode D _1u and the auxiliary diode D _2u ;

A resonant capacitor C _ru is connected in parallel between the emitter and the collector of the main switching tube T _1u , or a resonant capacitor C _ru is connected in parallel between the source and the drain of the main switching tube T _1u .

The resonant capacitor C _ru is a parasitic capacitor of the main switch T _1u or an external capacitor.

The second main power circuit includes:

_The main switching tube T _1d and the main inductor L _Fd , the emitter or source of the main switching tube T _1d is connected to the negative pole of the DC power supply S2, and the collector or drain of the main switching tube T _1d is connected to the main inductor L _Fd One end, the other end of the main inductance L _Fd is connected to the positive pole of the DC power supply S2 _;

The common point of the main switching tube T _1d and the main inductor _{LFd is connected to the anode of the main diode D Fd ,} and the cathode of the main diode D _Fd is connected to the common point of the central capacitor C _cen and the negative pole of the DC power supply S ₁ ;

_The negative pole of the DC power supply S2 is connected to the emitter or source of the auxiliary switching tube _T2d , the collector or drain of the auxiliary switching tube _T2d is connected to one end of the resonant inductor _Lrd , and the other end of the resonant inductor _Lrd is connected to the main switch At the common point of the tube T _1d and the main inductance L _Fd ;

The common point of the resonant inductance L _rd and the auxiliary switching tube T _2d is connected to the anode of the auxiliary diode D _1d , the cathode of the auxiliary diode D _1d is connected to the anode of the auxiliary diode D _2d , and the cathode of the auxiliary diode D _2d is connected to the central capacitor C The common point between _cen and the negative pole _of DC power supply S1;

The anode of the main diode D _Fd is connected to one end of the capacitor C _Bd , and the other end of the capacitor C _Bd is connected to the common point of the auxiliary diode D _1d and the auxiliary diode D _2d ;

A resonant capacitor C _rd is connected in parallel between the emitter and the collector of the main switching tube T _1d , or a resonant capacitor C _rd is connected in parallel between the source and the drain of the main switching tube T _1d .

The resonant capacitor C _rd is a parasitic capacitor of the main switching transistor T _1d or an external capacitor.

The latter stage circuit is a power conversion circuit including switching elements or linear elements.

A working method of a zero-voltage switching power supply-capacitor series DC converter, comprising:

The main switching tubes T _1u , T _1d and the auxiliary switching tubes T _2u , T _2d are controlled by the control circuit to turn on and off respectively. Describe the main switching tube T _1d and the auxiliary switching tube T _2d in the second main power circuit. The control timing is the same as that of the main switching transistor T _1u and the auxiliary switching transistor T _2u in the first main power circuit.

The main switching tube T _1u and the auxiliary switching tube T _2u in the first main power circuit include seven working modes in one switching cycle of the control circuit:

(1) t ₀ ≤t<t Mode 1 of ₂ stages:

At t ₀ , the auxiliary switch T _2u is turned on, and the voltage across the resonant inductor L _ru is V _s1 +V _cen ; at t ₁ , the current of the main diode D _Fu drops to 0; at t ₂ , the peak value of the reverse recovery current is reached, and the main diode D _Fu is completely cut off, where t ₀ <t ₁ <t ₂ ;

(2) t ₂ ≤t<t Mode 2 of ₃ stages:

From time t ₂ , the resonant inductor L _ru and the resonant capacitor C _ru resonate in parallel along the path L _ru -C _ru -T _2u , the resonant capacitor C _ru discharges, and the resonant inductor L _ru charges; until t ₃ , the resonant inductor L _ru The current reaches its maximum value, and the voltage of the resonant capacitor C _ru reaches zero;

(3) Mode 3 of t ₃ ≤t<t ₄ stages:

At time _t3 , the voltage of the resonant capacitor C _ru reaches zero, and then the anti-parallel diode of the main switching tube T _1u is turned on, part of the current of the resonant inductor L _ru flows back to the DC power supply through the main inductor L _Fu , and part of the current flows through the reverse circuit of the main switching tube T _1u The parallel diode and the auxiliary switching tube T _2u flow back to the resonant inductance L _ru ;

(4) Mode 4 of t ₄ ≤ t < t ₅ stage:

_At time t4, a turn-on signal is applied to the gate of the main switching tube T _1u , and the main switching tube T _1u is turned on with zero voltage; at the same time, a turn-off signal is applied to the gate of the auxiliary switching tube T _2u , and the auxiliary switching tube T _2u is turned off with zero voltage Then, the auxiliary diode D _1u is turned on with zero voltage, and the resonant inductance L _ru and the capacitor C _Bu undergo series resonance along the path L _ru -C _Bu -D _1u ;

(5) Mode 5 of t ₅ ≤ t < t ₆ stages:

At time t ₅ , the series resonance ends, the current of the resonant inductor L _ru is zero, and the voltage of the capacitor C _Bu is V _S1 +V _cen ; the current of the DC power supply S ₁ flows through the main switching tube T _1u and the main inductor L _Fu , and the DC power supply S ₁ is The main inductor L _Fu is charged;

(6) Mode 6 of t ₆ ≤ t < t ₇ stage:

At time t ₆ , a turn-off signal is applied to the gate of the main switching tube T _1u , and the main switching tube T _1u is turned off with zero voltage; then, part of the current of the main inductor L _Fu passes through the L _Fu –S ₁ –C _ru circuit, and the other part of the main switching tube T 1u Inductor L _Fu current flows through L _Fu –C _cen –D _2u –C _Bu loop;

(7) Mode 7 of t ₇ ≤ t < t ₈ stage:

From time t ₇ , the main diode D _Fu is turned on; the current of the main inductor L _Fu flows through the loop of L _Fu –C _cen –D _Fu , and the main inductor L _Fu charges the central capacitor C _cen ; at time t ₈ , the auxiliary switch tube T _2u again When it is turned on, one switching cycle of the zero-voltage conversion power supply-capacitor series DC converter ends; in the above process, the power supply circuit supplies power to the subsequent stage circuit or load.

The beneficial effects of the present invention are:

(1) The present invention greatly reduces the switching loss of the main switching tube and the main diode of the power supply-capacitor series DC converter, and greatly improves the conversion efficiency of the converter;

(2) The zero-voltage conversion power supply-capacitor series DC converter of the present invention has a boost function. Compared with the traditional DC boost circuit, the circuit greatly reduces the number of switches and diodes without increasing the current stress. voltage stress, thereby greatly reducing the switching loss of power semiconductor devices; the zero-voltage conversion auxiliary circuit of the present invention hardly increases the loss of the system, so that the overall efficiency is greatly improved;

(3) The zero-voltage conversion power supply-capacitor series DC converter of the present invention well solves the problem that the voltage and current stress of the traditional boost converter are relatively high, and simultaneously realizes the conversion of two or more The maximum power point tracking and DC boost function of an independent photovoltaic array, especially suitable for distributed photovoltaic grid-connected inverters, has high practical value; and greatly reduces the main diode of the power-capacitor series DC converter The peak value of the reverse recovery current effectively reduces the EMI of the system.

Description of drawings

Fig. 1 is the structure schematic diagram of zero-voltage switching power supply-capacitor series DC converter of the present invention;

Fig. 2 is the control signal of the first main power circuit of the present invention and each device voltage, electric current time-domain waveform diagram;

Fig. 3(a) is an equivalent circuit diagram of the first main power circuit of the present invention in switching mode 1 (t ₀ ≤ t < t ₂ );

Fig. 3(b) is an equivalent circuit diagram of the first main power circuit of the present invention in switching mode 2 (t ₂ ≤ t < t ₃ );

Fig. 3(c) is an equivalent circuit diagram of the first main power circuit of the present invention in switching mode 3 (t ₃ ≤ t < t ₄ );

Fig. 3(d) is an equivalent circuit diagram of the first main power circuit of the present invention in switching mode 4 (t ₄ ≤ t < t ₅ );

Fig. 3(e) is an equivalent circuit diagram of the first main power circuit of the present invention in switching mode 5 (t ₅ ≤ t < t ₆ );

Fig. 3(f) is an equivalent circuit diagram of the first main power circuit of the present invention in switching mode 6 (t ₆ ≤ t < t ₇ );

Fig. 3(g) is an equivalent circuit diagram of the first main power circuit of the present invention in switching mode 7 (t ₇ ≤ t < t ₈ ).

detailed description

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

As shown in Figure 1, a zero-voltage conversion power supply-capacitor series DC converter includes: a power supply circuit and a main power circuit;

The power supply circuit includes a DC power supply S ₁ , a central capacitor C _cen and a DC power supply S ₂ sequentially connected in series, and the power supply circuit supplies power to subsequent circuits or loads;

The main power circuit includes a first main power circuit and a second main power circuit, and the first main power circuit is connected in parallel between the central capacitor C _cen and the common point of the DC power supply S ₂ and the positive pole of the DC power supply S ₁ ; The second main power circuit is connected in parallel between the common point of the central capacitor C _cen and the DC power source S ₁ and the negative pole of the DC power source S ₂ .

The first main power circuit includes:

The main switching tube T _1u and the main inductor L _Fu , the collector or drain of the main switching tube T _1u is connected to the positive pole of the DC power supply S ₁ , the emitter or source of the main switching tube T _1u is connected to the main inductor L _Fu One end is connected, and the other end of the main inductor L _Fu is connected to the negative pole _of the DC power supply S1;

The common point of the main switching tube T _1u and the main inductor L _Fu is connected to the cathode of the main diode D _Fu , and the anode of the main diode D _Fu is connected to the common point of the positive pole of the DC power supply S ₂ and the central capacitor C _cen ;

The anode of the DC power supply S ₁ is connected to the collector or drain of the auxiliary switching tube T _2u , the emitter or source of the auxiliary switching tube T _2u is connected to one end of the resonant inductance L _ru , and the other end of the resonant inductance L _ru is connected to the main The common point of the switching tube T _1u and the main inductance L _Fu ;

The common point of the resonant inductance L _ru and the auxiliary switching tube T _2u is connected to the cathode of the auxiliary diode D _1u , the anode of the auxiliary diode D _1u is connected to the cathode of the auxiliary diode D _2u , and the anode of the auxiliary diode D _2u is connected to the DC power supply S ₂ The common point of the positive electrode and the central capacitor C _cen ;

The cathode of the main diode D _Fu is connected to one end of the capacitor C _Bu , and the other end of the capacitor C _Bu is connected to the common point of the auxiliary diode D _1u and the auxiliary diode D _2u ;

A resonant capacitor C _ru is connected in parallel between the emitter and the collector of the main switching tube T _1u , or a resonant capacitor C _ru is connected in parallel between the source and the drain of the main switching tube T _1u .

The resonant capacitor C _ru is a parasitic capacitor of the main switch T _1u or an external capacitor.

The second main power circuit includes:

_The main switching tube T _1d and the main inductor L _Fd , the emitter or source of the main switching tube T _1d is connected to the negative pole of the DC power supply S2, and the collector or drain of the main switching tube T _1d is connected to the main inductor L _Fd One end, the other end of the main inductance L _Fd is connected to the positive pole of the DC power supply S2 _;

The common point of the main switching tube T _1d and the main inductor _{LFd is connected to the anode of the main diode D Fd ,} and the cathode of the main diode D _Fd is connected to the common point of the central capacitor C _cen and the negative pole of the DC power supply S ₁ ;

_The negative pole of the DC power supply S2 is connected to the emitter or source of the auxiliary switching tube _T2d , the collector or drain of the auxiliary switching tube _T2d is connected to one end of the resonant inductor _Lrd , and the other end of the resonant inductor _Lrd is connected to the main switch At the common point of the tube T _1d and the main inductance L _Fd ;

The common point of the resonant inductance L _rd and the auxiliary switching tube T _2d is connected to the anode of the auxiliary diode D _1d , the cathode of the auxiliary diode D _1d is connected to the anode of the auxiliary diode D _2d , and the cathode of the auxiliary diode D _2d is connected to the central capacitor C The common point between _cen and the negative pole _of DC power supply S1;

The anode of the main diode D _Fd is connected to one end of the capacitor C _Bd , and the other end of the capacitor C _Bd is connected to the common point of the auxiliary diode D _1d and the auxiliary diode D _2d ;

A resonant capacitor C _rd is connected in parallel between the emitter and the collector of the main switching tube T _1d , or a resonant capacitor C _rd is connected in parallel between the source and the drain of the main switching tube T _1d .

The resonant capacitor C _rd is a parasitic capacitor of the main switching transistor T _1d or an external capacitor.

The latter stage circuit is a power conversion circuit including switching elements or linear elements.

The working method of the zero-voltage switching power supply-capacitor series DC converter in this embodiment includes:

The main switching tubes T _1u , T _1d and the auxiliary switching tubes T _2u , T _2d are controlled by the control circuit to turn on and off respectively, wherein the control circuit can be a PWM pulse generating circuit; in the first main power circuit, The timing sequence of the control signal of the main switching tube T _1u and the control signal of the auxiliary switching tube T _2u is shown in Figure 2; the control timing of the main switching tube T _1d and the auxiliary switching tube T _2d in the second main power circuit The control timings of the main switching tube T _1u and the auxiliary switching tube T _2u in the circuit are the same.

In Figure 2, V _{GE, T1u} represents the gate voltage of the main switching tube T _1u , V _{GE, T2u} represents the gate voltage of the auxiliary switching tube T _2u , I _Lru represents the current flowing through the resonant inductor L _ru , and V _CBu represents the capacitance The voltage across C _Bu , V _{CE, T1u} represents the collector-emitter voltage of the main switching tube T _1u , I _{C, T1u} represents the collector current of the main switching tube T _1u , V _DFu represents the voltage across the main diode D _F , I _DFu Represents the current flowing through the main diode D _F , V _T2u represents the collector-emitter voltage of the auxiliary switching tube T _2u , V _D1u represents the voltage across the auxiliary diode D _1u , and V _D2u represents the voltage across the auxiliary diode D _2u .

Since the working principle of the second main power circuit is basically the same as that of the first main power circuit, only the working principle of the first main power circuit is described in detail here, and the working principle of the second main power circuit can be derived by analogy from the first main power circuit.

The first main power circuit of the present invention has seven working modes in one switching cycle of the control circuit, as shown in Figure 3(a) to Figure 3(g), and each working mode will be analyzed in detail below :

(1) Mode 1 (t ₀ ≤t<t ₂ ):

As shown in Figure 3(a), before time t ₀ , the main diode D _Fu is turned on, and the main inductor current I _Fu flows through the main inductor L _Fu , the central capacitor C _cen and the main diode D _Fu , and the main inductor L _Fu is the central Capacitor C _cen is charged. At time t ₀ , the auxiliary switching tube T _2u is turned on, the voltage across the resonant inductor L _ru is V _s1 +V _cen , its current increases linearly, and the current of the main diode D _Fu decreases linearly. At time t ₁ , the current of the main diode D _{Fu drops} to 0; then, due to the reverse recovery characteristic of the main diode, the current of the main diode D _Fu increases negatively. The peak value of the reverse recovery current is reached at time t ₂ , and the main diode D _Fu is completely cut off. Since the resonant inductance limits the di/dt value of the main diode D _Fu current, the main diode D _Fu is softly turned off, minimizing the reverse recovery loss. At the same time, the series circuit composed of the DC power supply S ₁ , the central capacitor C _cen and the DC power supply S ₂ supplies power to the subsequent power conversion circuit or load, where t ₀ <t ₁ <t ₂ .

(2) Mode 2 (t ₂ ≤t<t ₃ ):

As shown in Figure 3(b), starting from time _t2 , the resonant inductor L _ru and the resonant capacitor C _ru resonate in parallel along the path L _ru -C _ru -T _2u , the resonant capacitor C _ru is discharged, and the resonant inductor L _ru is charged. Until _t3 , the current of the resonant inductor L _ru reaches its maximum value, and the voltage of the resonant capacitor C _ru reaches zero. This creates conditions for the zero-voltage turn-on of the main switching tube T _1u . The current waveform of the resonant inductor L _ru and the voltage waveform of the resonant capacitor C _ru are shown in Fig. 2 . At the same time, the series circuit composed of the DC power source S ₁ , the central capacitor C _cen and the DC power source S ₂ supplies power to the subsequent power conversion circuit or load.

(3) Mode 3 (t ₃ ≤t<t ₄ ):

As shown in Figure ₃ (c), at time t3, the voltage of the resonant capacitor C _ru reaches zero, and then the anti-parallel diode of the main switching tube T _1u conducts, and part of the current of the resonant inductor L _ru flows back to the DC power supply through the main inductor L _Fu , Part of it flows back to the resonant inductor L _ru through the anti-parallel diode of the main switching tube T _1u and the auxiliary switching tube T _2u . At the same time, the series circuit composed of the DC power source S ₁ , the central capacitor C _cen and the DC power source S ₂ supplies power to the subsequent power conversion circuit or load.

(4) Mode 4 (t ₄ ≤t<t ₅ ):

As shown in Figure 3( _d ), at time t4, a turn-on signal is applied to the gate of the main switching tube T _1u , and the main switching tube T _1u is turned on with zero voltage and starts to pass current. At the same time, a shutdown signal is applied to the gate of the auxiliary switching transistor T _2u , and the auxiliary switching transistor T _2u is turned off with zero voltage. Subsequently, the auxiliary diode D _1u is turned on with zero voltage, and the resonant inductor L _ru and the capacitor C _Bu undergo series resonance along the path L _ru -C _Bu -D _1u . The resonant inductor L _ru discharges, and its current drops; the capacitor C _Bu is charged, and the voltage across it rises. By properly selecting the capacitance of the capacitor C _Bu , it can be realized that the voltage across the capacitor C _Bu is exactly V _S1 +V _cen at the end of the resonance. At the same time, the series circuit composed of the DC power source S ₁ , the central capacitor C _cen and the DC power source S ₂ supplies power to the subsequent power conversion circuit or load.

(5) Mode 5 (t ₅ ≤t<t ₆ ):

As shown in Fig. ₃ (e), at time t5, the series resonance ends, the current of the resonant inductor L _ru is zero, and the voltage of the capacitor C _Bu is V _S1 +V _cen . The current of the DC power source S ₁ flows through the main switching tube T _1u and the main inductor L _Fu , and the DC power source S ₁ charges the main inductor L _Fu . At the same time, the series circuit composed of the DC power source S ₁ , the central capacitor C _cen and the DC power source S ₂ supplies power to the subsequent power conversion circuit or load.

(6) Mode 6 (t ₆ ≤t<t ₇ ):

As shown in Figure ₃ (f), at time t6, a shutdown signal is applied to the gate of the main switching tube T _1u , and the main switching tube T _1u is turned off with zero voltage. Subsequently, a part of the main inductor L _Fu current passes through the L _Fu –S ₁ –C _ru loop, and another part of the main inductor L _Fu current passes through the L _Fu –C _cen –D _2u –C _Bu loop. The resonant capacitor C _ru is charged, and its voltage rises; the capacitor C _Bu is discharged, and its voltage drops. At the same time, the series circuit composed of the DC power source S ₁ , the central capacitor C _cen and the DC power source S ₂ supplies power to the subsequent power conversion circuit or load.

(7) Mode 7 (t ₇ ≤t<t ₈ ):

As shown in _Fig . 3(g), at time t7, the voltage of the resonant capacitor C _ru rises to V _S1 +V _cen , while the voltage of the capacitor C _Bu drops to zero. From time t ₇ , the main diode D _Fu is turned on. The current of the main inductor L _Fu flows through the loop of L _Fu –C _cen –D _Fu , and the main inductor L _Fu charges the central capacitor C _cen . At the same time, the series circuit composed of the DC power source S ₁ , the central capacitor C _cen and the DC power source S ₂ supplies power to the subsequent power conversion circuit or load. At time t ₈ , the auxiliary switching tube T _2u is turned on again, and a switching cycle of the zero-voltage switching power supply-capacitor series DC converter ends.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (8)

1. Zero voltage transition power supply-capacitances in series type DC converter, is characterized in that, comprising: power circuit and main power circuit;

Described power circuit, comprises the DC power supply S be sequentially connected in series ₁, central electric capacity C _cenand DC power supply S ₂, described power circuit is late-class circuit or load supplying;

Described main power circuit, comprises the first main power circuit and the second main power circuit, and described first main power circuit is connected in parallel on central electric capacity C _cenwith DC power supply S ₂common point and DC power supply S ₁positive limit between; Described second main power circuit is connected in parallel on central electric capacity C _cenwith DC power supply S ₁common point and DC power supply S ₂negative pole point between.

2. a kind of Zero voltage transition power supply-capacitances in series type DC converter as claimed in claim 1, it is characterized in that, described first main power circuit, comprising:

Main switch T _1uwith main inductance L _fu, described main switch T _1ucollector electrode or drain electrode and DC power supply S ₁positive pole be connected, main switch T _1uemitter-base bandgap grading or source electrode and main inductance L _fuone end be connected, main inductance L _futhe other end and DC power supply S ₁negative pole be connected;

Described main switch T _1uwith main inductance L _fucommon point and main diode D _funegative electrode be connected, main diode D _fuanode be connected to DC power supply S ₂positive pole and central electric capacity C _cencommon point;

Described DC power supply S ₁positive pole connects auxiliary switch pipe T _2ucollector electrode or drain electrode, auxiliary switch pipe T _2uemitter-base bandgap grading or source electrode be connected to resonant inductance L _ruone end, resonant inductance L _ruthe other end be connected to main switch T _1uwith main inductance L _fucommon point;

Described resonant inductance L _ruwith auxiliary switch pipe T _2ucommon point connect auxiliary diode D _1unegative electrode, auxiliary diode D _1uanode connect auxiliary diode D _2unegative electrode, auxiliary diode D _2uanode be connected to DC power supply S ₂positive pole and central electric capacity C _cencommon point;

Described main diode D _funegative electrode be connected to electric capacity C _buone end, electric capacity C _buthe other end be connected to auxiliary diode D _1uwith auxiliary diode D _2ucommon point;

Described main switch T _1uemitter-base bandgap grading and collector electrode two ends be parallel with resonant capacitance C _ru, or main switch T _1usource electrode with drain electrode two ends be parallel with resonant capacitance C _ru.

3. a kind of Zero voltage transition power supply-capacitances in series type DC converter as claimed in claim 2, is characterized in that, described resonant capacitance C _rufor main switch T _1uparasitic capacitance or external capacitor.

4. a kind of Zero voltage transition power supply-capacitances in series type DC converter as claimed in claim 1, it is characterized in that, described second main power circuit, comprising:

Main switch T _1dwith main inductance L _fd, described main switch T _1demitter-base bandgap grading or source electrode be connected to DC power supply S ₂negative pole, main switch T _1dcollector electrode or drain electrode be connected to main inductance L _fdone end, main inductance L _fdthe other end connect DC power supply S ₂positive pole;

Described main switch T _1dwith main inductance L _fdcommon point and main diode D _fdanode be connected, main diode D _fdnegative electrode be connected to central electric capacity C _cenwith DC power supply S ₁the common point of negative pole;

Described DC power supply S ₂negative pole connects auxiliary switch pipe T _2demitter-base bandgap grading or source electrode, auxiliary switch pipe T _2dcollector electrode or drain electrode connect resonant inductance L _rdone end, resonant inductance L _rdthe other end be connected to main switch T _1dwith main inductance L _fdcommon point place;

Described resonant inductance L _rdwith described auxiliary switch pipe T _2dcommon point connect auxiliary diode D _1danode, auxiliary diode D _1dnegative electrode connect auxiliary diode D _2danode, auxiliary diode D _2dnegative electrode be connected to central electric capacity C _cenwith DC power supply S ₁the common point of negative pole;

Described main diode D _fdanode connect electric capacity C _bdone end, electric capacity C _bdthe other end be connected to auxiliary diode D _1dwith auxiliary diode D _2dcommon point place;

Described main switch T _1demitter-base bandgap grading and collector electrode two ends be parallel with resonant capacitance C _rd, or main switch T _1dsource electrode with drain electrode two ends be parallel with resonant capacitance C _rd.

5. a kind of Zero voltage transition power supply-capacitances in series type DC converter as claimed in claim 4, is characterized in that, described resonant capacitance C _rdfor main switch T _1dparasitic capacitance or external capacitor.

6. a kind of Zero voltage transition power supply-capacitances in series type DC converter as claimed in claim 1, is characterized in that, described late-class circuit is the power conversion circuit containing switch element or linear element.

7. a method of work for Zero voltage transition power supply according to claim 1-capacitances in series type DC converter, is characterized in that, comprising:

Main switch T _1u, T _1dwith auxiliary switch pipe T _2u, T _2dits conducting and the shutoff separately of all controlled control circui, the main switch T in the second main power circuit _1d, auxiliary switch pipe T _2dcontrol timing sequence and the first main power circuit in main switch T _1u, auxiliary switch pipe T _2ucontrol timing sequence identical.

8. the method for work of Zero voltage transition power supply-capacitances in series type DC converter as claimed in claim 7, is characterized in that, the main switch T in described first main power circuit _1uwith auxiliary switch pipe T _2useven operation modes are comprised in a switch periods of control circuit:

(1) t ₀≤ t<t ₂the mode 1 in stage:

T ₀moment, auxiliary switch pipe T _2uopen-minded, resonant inductance L _ruboth end voltage is V _s1+ V _cen; t ₁moment, main diode D _fuelectric current reduces to 0; t ₂moment reaches reverse recovery current peak value, main diode D _fuend completely, wherein t ₀<t ₁<t ₂;

(2) t ₂≤ t<t ₃the mode 2 in stage:

From t ₂moment, resonant inductance L _ruwith resonant capacitance C _rualong path L _ru– C _ru– T _2uthere is parallel resonance, resonant capacitance C _ruelectric discharge, resonant inductance L _rucharging; Until t ₃moment, resonant inductance L _ruelectric current reaches its maximum, resonant capacitance C _ruvoltage reaches zero;

(3) t ₃≤ t<t ₄the mode 3 in stage:

T ₃moment, resonant capacitance C _ruvoltage reaches zero, subsequently main switch T _1uanti-paralleled diode conducting, resonant inductance L _ruan electric current part is through main inductance L _fuflow back to DC power supply, a part is through main switch T _1uanti-and diode, auxiliary switch pipe T _2uflow back to resonant inductance L _ru;

(4) t ₄≤ t<t ₅the mode 4 in stage:

T ₄moment, to main switch T _1ugate pole apply open signal, main switch T _1uno-voltage is open-minded; Meanwhile, to auxiliary switch pipe T _2ugate pole apply cut-off signals, auxiliary switch pipe T _2uzero voltage turn-off; Subsequently, auxiliary diode D _1uno-voltage is open-minded, resonant inductance L _ruwith electric capacity C _bualong path L _ru– C _bu– D _1uthere is series resonance;

(5) t ₅≤ t<t ₆the mode 5 in stage:

T ₅in the moment, series resonance terminates, resonant inductance L _ruelectric current is zero, electric capacity C _buvoltage is V _s1+ V _cen; DC power supply S ₁electric current flows through main switch T _1uwith main inductance L _fu, DC power supply S ₁for main inductance L _fucharging;

(6) t ₆≤ t<t ₇the mode 6 in stage:

T ₆moment, to main switch T _1ugate pole apply cut-off signals, main switch T _1uzero voltage turn-off; Subsequently, a part of main inductance L _fuelectric current is through L _fu– S ₁– C _ruloop, another part main inductance L _fucircuit current is through L _fu– C _cen– D _2u– C _buloop;

(7) t ₇≤ t<t ₈the mode 7 in stage:

From t ₇moment, main diode D _fuopen-minded; Main inductance L _fuelectric current flows through L _fu– C _cen– D _fuloop, main inductance L _fufor central electric capacity C _cencharging; t ₈moment, auxiliary switch pipe T _2uconducting again, a switch periods of Zero voltage transition power supply-capacitances in series type DC converter terminates; Power circuit is late-class circuit or load supplying in above process.