CN102769377B - Non-isolated variable flow topological structure based on phase shift control and application thereof - Google Patents

Abstract

The invention provides a non-isolated converter topology based on phase shift control, which includes a switched capacitor circuit and a transformer circuit; wherein, the switched capacitor circuit consists of two switch tubes, a high-voltage capacitor, a resonant capacitor and a The resonant inductance is connected, and the voltage transformation circuit is composed of two switch tubes, a high-voltage capacitor and a filter inductance connected; the invention also discloses a converter adopting the topological structure. The invention realizes the control of the energy flow direction and the voltage balance of each capacitor on the high-voltage side through the control of the phase shift angle and duty ratio of different switch tubes, and realizes the adjustment of the output voltage in a wide range, and the zero-voltage on-off of each switch tube. The converter of the present invention utilizes the cascaded structure of multiple sets of switched capacitor circuits to realize a higher step-down ratio output of the converter, reduce the voltage stress of each device, further improve the step-down ratio of the converter by using the transformer circuit, reduce the voltage stress, and The output voltage can be adjusted.

Description

A non-isolated inverter topology based on phase-shift control and its application

technical field

The invention belongs to the technical field of power conversion, in particular to a non-isolated converter topology based on phase-shift control and its application.

Background technique

In recent years, energy shortage and environmental pollution have become the focus of the world, and the development and application of renewable energy have attracted widespread attention from all over the world. In the renewable energy power generation system, the electric energy generated by many renewable energy sources is low-voltage direct current, and high-voltage direct current is required for power transmission to the grid, so a DC-DC converter is required to convert low-voltage direct current into suitable and The high-voltage direct current of the grid, so low input ripple, high gain, and high-efficiency converters play an important role in the field of renewable energy grid-connected power generation; at the same time, some electrical loads have low operating voltages and require DC-DC The converter converts the high voltage direct current into a low voltage direct current suitable for the electrical load.

The traditional BUCK converter is shown in Figure 1. It has a simple structure and is widely used. However, the power switch tube of this converter works in a hard switching state, and the switching loss and voltage stress of the power switch tube are large. In the application of the step-down ratio, the current fluctuation on the input side is large, and the use of a large series inductor on the output side will further increase the cost and size and reduce the efficiency.

The traditional flyback circuit is shown in Figure 2. Its topology can achieve a high step-down ratio through the transformer ratio, but all power transmission needs to pass through the magnetic core, which increases the volume of the converter to a certain extent and brings There is a certain electromagnetic interference problem.

In recent years, some switched capacitor converters have appeared one after another. Based on the topology of the voltage equalizing switched capacitor converter, a resonant phase-shifting circuit is added to realize the soft switching of the power switch tube; the typical resonant The topology of the switched capacitor converter is shown in Figure 3. This topology has the advantage of zero-current switching, but the output voltage of the resonant switched capacitor converter is determined by the specific topology of the circuit, and the output voltage cannot be controlled by the duty cycle. , which limits the adjustable range of the output voltage of the converter, and the energy cannot flow in both directions.

Contents of the invention

Aiming at the above-mentioned technical defects in the prior art, the present invention provides a non-isolated converter topology based on phase-shift control and its application, which has high voltage drop ratio, simple structure, high efficiency, and adjustable output voltage.

A non-isolated converter topology based on phase-shift control, including a switched capacitor circuit and a transformer circuit;

The switched capacitor circuit is composed of two switch tubes S ₁ -S ₂ , a high-voltage capacitor C ₁ , a resonant capacitor C _r and a resonant inductance L _r ; wherein, the input terminal of the switch tube S ₁ is connected to the high-voltage capacitor C ₁ One end of the switch tube _S1 is connected to the input end of the switch tube _S2 and one end of the resonant inductance L _r , the output end of the switch tube _S2 is connected to the other end of the high-voltage capacitor _C1 , and the resonant inductance L _r The other end is connected to one end of the resonant capacitor C _r , and the other end of the resonant capacitor C _r is connected to the transformer circuit;

The voltage transformation circuit is composed of two switch tubes S ₃ -S ₄ , a high-voltage capacitor C ₂ and a filter inductor L _f ; wherein, the input end of the switch tube S ₃ and one end of the high-voltage capacitor C ₂ and the switched capacitor circuit The other end of the middle and high voltage capacitor C ₁ is connected, the output end of the switch tube S ₃ is connected with the input end of the switch tube S ₄ , one end of the filter inductance L _f is connected with the other end of the resonant capacitor C _r in the switched capacitor circuit, and the switch tube S ₄ The output terminal of the high voltage capacitor _C2 is connected to the other end;

The control terminal of the switch tube receives a control signal provided by an external device.

One end of the high-voltage capacitor _C1 and the other end of the high-voltage capacitor _C2 constitute the high-voltage side, and the other end of the filter inductor _Lf and the other end of the high-voltage capacitor _C2 constitute the low-voltage side;

When the high-voltage side is used as the input and the low-voltage side is used as the output, an output capacitor C _out is connected between the other end of the filter inductor L _f and the other end of the high-voltage capacitor C ₂ .

The control signal received by the switch tube _S1 is complementary in phase to the control signal received by the switch tube _S2 and there is a dead interval; the control signal received by the switch tube _S3 is complementary in phase to the control signal received by the switch tube _S4 and there is a dead zone interval. Interval: the control signal received by the switch tube _S1 has the same duty cycle as the control signal received by the switch tube _S3 , and there is a phase shift angle.

Preferably, the switching tube is a MOS tube; the switching frequency of the MOS tube is high, and the device is equipped with an anti-parallel diode, and the topological structure constructed by using the MOS tube is smaller in size and high in power density.

The principle of the inverter topology structure of the present invention is: by controlling the phase-shift angle of the control signal of the switch tube _S1 and the control signal of the switch tube _S3 , the high-voltage capacitor equalization and power flow control are realized; when the phase-shift angle is 0, the high-voltage No energy is transmitted between capacitor _C1 and high-voltage capacitor _C2 , and the voltage is balanced; when the phase shift angle is greater than 0 ( _S1 is turned on prior to _S3 ), _C1 transmits energy to _C2 , and the system moves from the high-voltage side to the low-voltage side Transmission of energy; when the phase shift angle is less than 0 (S ₁ lags behind S ₃ to conduct), C ₂ transmits energy to C ₁ , and the system transmits energy from the low-voltage side to the high-voltage side. When the high-voltage side transmits power to the low-voltage side, a BUCK circuit is composed of capacitor C ₂ , switch tubes S ₃ and S ₄ , filter inductor L _f and output capacitor C _out , and the phase shift angle can be adjusted to make the voltage on C ₂ a high voltage Half of the input voltage on the low-voltage side, the output voltage on the low-voltage side is the product of the voltage on _C2 and the duty cycle D of the _S1 control signal. When the low-voltage side transmits power to the high-voltage side, capacitor C ₂ , switch tubes S ₃ and S ₄ and filter inductor L _f form a BOOST circuit. The voltage on C ₂ is the input voltage of the low-voltage side divided by the duty cycle D to adjust the phase shift Angle, can make the output voltage of the high voltage side twice the voltage of the capacitor _C2 .

A non-isolated converter based on phase-shift control, comprising n switched capacitor circuits and a transformer circuit, wherein n switched capacitor circuits are sequentially cascaded, and n is a natural number greater than 1;

The switched capacitor circuit is composed of two switch tubes S ₁ -S ₂ , a high-voltage capacitor C ₁ , a resonant capacitor C _r and a resonant inductance L _r ; wherein, the input terminal of the switch tube S ₁ is connected to the high-voltage capacitor C ₁ One end is connected to the first input end of the switched capacitor circuit, the output end of the switch tube _S1 is connected to the input end of the switch tube _S2 and one end of the resonant inductance _Lr and is the second input end of the switched capacitor circuit, the switch tube The output terminal of S ₂ is connected with the other end of the high-voltage capacitor C ₁ and is the first output terminal of the switched capacitor circuit, the other end of the resonant inductor L _r is connected with one end of the resonant capacitor C _r , and the other end of the resonant capacitor C _r is a switch a second output terminal of the capacitor circuit;

The first output end of the i-1th switched capacitor circuit is connected to the first input end of the i-th switched capacitor circuit, the second output end of the i-1th switched capacitor circuit is connected to the second input end of the i-th switched capacitor circuit, i is a natural number and 2≤i≤n;

The voltage transformation circuit is composed of two switching tubes S ₃ -S ₄ , a high-voltage capacitor C ₂ and a filter inductance L _f ; wherein, the input end of the switching tube S ₃ is connected to one end of the high-voltage capacitor C ₂ and the nth switch The first output end of the capacitor circuit is connected, the output end of the switch tube _S3 is connected with the input end of the switch tube _S4 , one end of the filter inductance L _f is connected with the second output end of the nth switched capacitor circuit, and the output of the switch tube _S4 The end is connected with the other end of the high-voltage capacitor _C2 ;

The control terminal of the switch tube receives a control signal provided by an external device.

The first input terminal of the first switched capacitor circuit and the other end of the high-voltage capacitor _C2 form a high-voltage side, and the other end of the filter inductance L _f and the other end of the high-voltage capacitor _C2 form a low-voltage side;

When the high-voltage side is used as the input and the low-voltage side is used as the output, an output capacitor C _out is connected between the other end of the filter inductor L _f and the other end of the high-voltage capacitor C ₂ .

The control signal received by the switch tube _S1 is complementary in phase to the control signal received by the switch tube _S2 and there is a dead interval; the control signal received by the switch tube _S3 is complementary in phase to the control signal received by the switch tube _S4 and there is a dead zone interval. Interval: the control signal received by the switch tube _S1 has the same duty cycle as the control signal received by the switch tube _S3 , and there is a phase shift angle.

The principle of the converter of the present invention is: by controlling the phase-shift angle of the control signal of the switch tube _S1 and the control signal of the switch tube _S3 to realize high-voltage capacitor balance and power flow control; when the phase-shift angle is 0, each high-voltage No energy is transmitted between capacitors, nor is energy transmitted by the system;

When the phase shift angle is greater than 0 (S ₁ in the i-1 switched capacitor circuit is turned on prior to S 1 in the i switched capacitor circuit, and _{S 1 is} turned on prior to S ₃ in the fifth switched capacitor circuit), the i- 1 _C1 in the switched capacitor circuit transmits energy to _C1 in the i-th switched capacitor circuit, _C1 transmits energy to _C2 in the fifth switched capacitor circuit, and the system transmits energy from the high voltage side to the low voltage side;

When the phase shift angle is less than 0 (S ₁ in the i-1 switched capacitor circuit lags behind S 1 in the i switched capacitor circuit, and _{S 1 lags} behind S ₃ in the fifth switched capacitor circuit), the i switch C ₁ in the capacitor circuit transmits energy to C 1 in the i-1th switched capacitor circuit, C ₂ transmits energy to _{C 1 in} the fifth switched capacitor circuit, and the system transmits energy from the low voltage side to the high voltage side.

When the high-voltage side transmits power to the low-voltage side, a BUCK circuit is composed of capacitor C ₂ , switch tubes S ₃ and S ₄ , filter inductor L _f and output capacitor C _out . Adjusting the phase shift angle can make the high-voltage capacitors equalize and It is 1/n+1 of the input voltage on the high-voltage side, the output voltage on the low-voltage side is the product of the voltage on _C2 and the duty ratio D of the control signal of _S1 , and the system transformation ratio is D/n+1. When the low-voltage side transmits power to the high-voltage side, capacitor C ₂ , switch tubes _S 3 and S ₄ and filter inductor L _f form a BOOST circuit. The voltage on C ₂ is the input voltage of the low-voltage side divided by the duty cycle D to adjust the phase shift The angle can make each high-voltage capacitor equalize, and the output voltage on the high-voltage side is n+1 times the voltage of capacitor _C2 , and the system transformation ratio is n+1/D.

The inverter structure of the present invention realizes the control of the energy flow direction and the voltage balance of each capacitor on the high-voltage side through the control of the phase shift angle between the transformer circuit and the switched capacitor circuit; through the control of the duty ratio of the upper switching tube in the circuit, The wide-range adjustment of the output voltage is realized; at the same time, the zero-voltage turn-off of each switch tube can be realized by using the parasitic capacitance of the switch tube; the zero-voltage turn-on of each switch tube can be realized by using the phase-shift control method of the resonant circuit. The converter of the present invention utilizes the cascaded structure of multiple sets of switched capacitor circuits to realize a higher step-down ratio output of the converter, reduce the voltage stress of each device, further improve the step-down ratio of the converter by using the transformer circuit, reduce the voltage stress, and The output voltage can be adjusted.

Description of drawings

Fig. 1 is a schematic structural diagram of a conventional BUCK converter circuit.

FIG. 2 is a schematic structural diagram of a traditional flyback converter circuit.

FIG. 3 is a schematic structural diagram of a resonant switched capacitor converter circuit.

Fig. 4 is a schematic diagram of the converter topology of the present invention.

FIG. 5 is a working waveform diagram of the present invention in the step-down mode of the converter topology.

Fig. 6 is a working waveform diagram in the boost mode of the converter topology of the present invention.

Fig. 7 is a schematic structural diagram of the converter of the present invention.

Detailed ways

In order to describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 4, a non-isolated converter topology based on phase-shift control includes a switched capacitor circuit and a transformer circuit;

The switched capacitor circuit is composed of two switch tubes S ₁ ~ S ₂ , a high voltage capacitor C ₁ , a resonant capacitor C _r and a resonant inductor L _r ; among them, the input end of the switch tube S ₁ is connected to one end of the high voltage capacitor C ₁ , the output end of the switch tube _S1 is connected with the input end of the switch tube _S2 and one end of the resonant inductance L _r , the output end of the switch tube _S2 is connected with the other end of the high-voltage capacitor _C1 , and the other end of the resonant inductance L _r is connected with One end of the resonant capacitor C _r is connected, and the other end of the resonant capacitor C _r is connected to the transformer circuit;

Transformer circuit is composed of two switch tubes S ₃ ~ S ₄ , a high-voltage capacitor C ₂ , an output capacitor C _out and a filter inductor L _f ; among them, the input end of the switch tube S ₃ and one end of the high-voltage capacitor C ₂ and The other end of the high-voltage capacitor _C1 in the switched capacitor circuit is connected, the output end of the switch tube _S3 is connected with the input end of the switch tube _S4 , one end of the filter inductance L _f is connected with the other end of the resonant capacitor C _r in the switched capacitor circuit, and the switch The output end of the tube S ₄ is connected to the other end of the high voltage capacitor C ₂ ; the output capacitor C _out is connected between the other end of the filter inductor L _f and the other end of the high voltage capacitor C ₂ .

One end of the high-voltage capacitor _C1 and the other end of the high-voltage capacitor _C2 form a high-voltage side and connect to a high-voltage power supply or a high-voltage load; the other end of the filter inductor _Lf and the other end of the high-voltage capacitor _C2 form a low-voltage side and connect to a low-voltage power supply or a low-voltage load .

The control terminal of the switch tube receives the control signal provided by the external device; in this embodiment, the control signal received by the switch tube _S1 is complementary to the control signal received by the switch tube _S2 and there is a dead interval; the control signal received by the switch tube _S3 The phase of the signal is complementary to that of the control signal received by the switch _S4 and there is a dead interval; the duty ratio of the control signal received by the switch _S1 is the same as that of the control signal received by the switch _S3 and there is a phase shift angle.

In this embodiment, since power-on and natural voltage equalization are required, C ₁ =C ₂ , the switching tubes are N-type MOS tubes, and the parameters of the switching tubes are basically the same.

When the phase shift angle is 0, the current of the resonant inductor L _r is 0, no energy is transmitted between C ₁ and C ₂ , and the voltage is balanced;

When the phase shift angle is greater than 0 (S ₁ takes precedence over S ₃ ), as shown in Figure 5, C ₁ transfers energy to C ₂ , and the system transfers energy from the high-voltage side to the low-voltage side, capacitor C ₂ , switch tube S ₃ and S _4. Filter inductance L _f and output capacitor C _out form a BUCK circuit, adjust the phase shift angle, so that the voltage on _C2 can be half of the input voltage on the high-voltage side, and the output voltage on the low-voltage side is the voltage on _C2 and the duty cycle D The product; the working status of the system is as follows:

Stage 1 (t ₀ -t ₁ ) S ₁ and S ₂ dead zone, the parasitic capacitance of S ₁ is discharged, and the parasitic capacitance of S ₂ is charged; S ₄ is turned on, and L _f releases energy to the low-voltage side. After S ₂ is turned off, the resonant inductor L _r sinks current into the S ₁ and S ₂ contacts. Due to the existence of the parasitic capacitance of S ₂ , the current flowing through S ₂ is zero, and the voltage rises slowly to V _C1 , realizing soft shutdown.

Phase 2 (t ₁ -t ₂ ) S ₁ and S ₄ are turned on, and the high voltage side begins to charge _Cr . After the parasitic capacitor voltage of S ₂ rises to V _C1 , the parasitic anti-parallel diode of S ₁ is turned on, and its drain-source voltage is 0. At this time, switch S ₁ is turned on, that is, zero-voltage turn-on is realized.

Phase 3 (t ₂ -t ₃ ) S ₁ and S ₄ are turned on, the high voltage side charges _Cr , the current _of Cr becomes positive, and S ₁ conducts forward.

Stage 4 (t ₃ -t ₄ ) S ₃ and S ₄ dead zone, the parasitic capacitance of S ₃ is discharged, and the parasitic capacitance of S ₄ is charged. After S ₄ is turned off, the resonant inductance L _r sinks current into the contacts of S ₃ and S ₄ , due to the existence of the parasitic capacitance of S ₄ , the current flowing through S ₄ is zero, and the voltage rises slowly to V _C2 , realizing soft shutdown.

Stage 5 (t ₄ -t ₅ ) S ₁ and S ₃ are turned on, C _r begins to absorb the energy of C ₁ , its current is relatively large, and the island between C ₁ and C ₂ absorbs charge. After the parasitic capacitor voltage of S ₄ rises to V _C2 , the parasitic anti-parallel diode of S ₃ is turned on, and its drain-source voltage is 0. At this time, switch S ₃ is turned on, that is, zero-voltage turn-on is realized.

Stage 6 (t ₅ -t ₆ ) S ₁ and S ₃ are turned on, C _r continues to absorb the energy of C ₁ , its current decreases, the island between C ₁ and C ₂ discharges charges, and S ₃ conducts forward.

Stage 7 (t ₆ -t ₇ ) S ₁ and S ₂ dead zone, the parasitic capacitance of S ₂ is discharged, and the parasitic capacitance of S ₁ is charged. After S ₁ is turned off, the resonant inductance L _r draws current from the junction of S ₁ and S ₂ . Due to the existence of the parasitic capacitance of S ₁ , the current flowing through S ₁ is zero, and the voltage rises slowly to V _C2 , realizing soft shutdown.

Stage 8 (t ₇ -t ₈ ) S ₂ and S ₃ are turned on, and _Cr begins to release energy. After the parasitic capacitor voltage of S ₁ rises to V _C1 , the parasitic anti-parallel diode of S ₂ is turned on, and its drain-source voltage is 0. At this time, switch S ₂ is turned on, that is, zero-voltage turn-on is realized.

Stage 9 (t ₈ -t ₉ ) S ₂ and S ₃ are turned on, _Cr continues to release energy, the current _{of Cr} becomes negative, and S ₂ conducts positively.

Stage 10 (t ₉ -t ₁₀ ) S ₃ and S ₄ dead zone, the parasitic capacitance of S ₄ is discharged, and the parasitic capacitance of S ₃ is charged. After S ₃ is turned off, the resonant inductance L _r draws current from the junction of S ₃ and S ₄ . Due to the existence of the parasitic capacitance of S ₃ , the current flowing through S ₃ is zero, and the voltage rises slowly to V _C2 , realizing soft shutdown.

Phase 11 (t ₁₀ -t ₁₁ ) S ₂ and S ₄ are turned on, and C _r releases energy to C ₂ . After the parasitic capacitance voltage of S ₃ rises to V _C2 , the parasitic anti-parallel diode of S ₄ is turned on, and its drain-source voltage is 0. At this time, the switch S ₄ is turned on, that is, zero-voltage turn-on is realized;

When the phase shift angle is less than 0 (S ₁ lags behind S ₃ ), as shown in Figure 6, C ₂ transfers energy to C ₁ , and the system transfers energy from the low-voltage side to the high-voltage side. Capacitor C ₂ , switch tube S ₃ and S ₄ and the filter inductance L _f form a BOOST circuit (remove the output capacitor C _out ), the voltage on C ₂ is the input voltage of the low voltage side divided by the duty cycle D, and the phase shift angle can be adjusted to make the output voltage of the high voltage side equal to the capacitor C ₂ twice the voltage; the working state of the system is as follows:

Phase 1 (t ₀ -t ₁ ) S ₃ and S ₄ dead zone, the parasitic capacitance of S ₃ is discharged, and the parasitic capacitance of S ₄ is charged. After S ₄ is turned off, the resonant inductance L _r sinks current into the contacts of S ₃ and S ₄ , due to the existence of the parasitic capacitance of S ₄ , the current flowing through S ₄ is zero, and the voltage rises slowly to V _C2 , realizing soft shutdown.

Phase 2 (t ₁ -t ₂ ) S ₂ and S ₃ are turned on, and C _r starts to release energy to L _r . After the parasitic capacitor voltage of S ₄ rises to V _C2 , the parasitic anti-parallel diode of S ₃ is turned on, and its drain-source voltage is 0. At this time, switch S ₃ is turned on, that is, zero-voltage turn-on is realized.

Stage 3 (t ₂ -t ₃ ) S ₂ and S ₃ are turned on, _Cr continues to release energy, the current _{of Cr} becomes negative, and S ₃ conducts positively.

Stage 4 (t ₃ -t ₄ ) S ₁ and S ₂ dead zone, the parasitic capacitance of S ₁ is discharged, and the parasitic capacitance of S ₂ is charged. After S ₂ is turned off, the resonant inductor L _r sinks current into the S ₁ and S ₂ contacts. Due to the existence of the parasitic capacitance of S ₂ , the current flowing through S ₂ is zero, and the voltage rises slowly to V _C1 , realizing soft shutdown.

Stage 5 (t ₄ -t ₅ ) S ₁ and S ₃ are turned on, C _r releases energy to C ₁ , L _f has a larger current, and the island between C ₁ and C ₂ absorbs charges. After the parasitic capacitor voltage of S ₂ rises to V _C1 , the parasitic anti-parallel diode of S ₁ is turned on, and its drain-source voltage is 0. At this time, switch S ₁ is turned on, that is, zero-voltage turn-on is realized.

Stage 6 (t ₅ -t ₆ ) S ₁ and S ₃ are turned on, C _r continues to release energy to C ₁ , the current of L _f decreases, and the island between C ₁ and C ₂ discharges charges.

Stage 7 (t ₆ -t ₇ ) S ₃ and S ₄ dead zone, the parasitic capacitance of S ₄ is discharged, and the parasitic capacitance of S ₃ is charged. After S ₃ is turned off, the resonant inductance L _r draws current from the junction of S ₃ and S ₄ . Due to the existence of the parasitic capacitance of S ₃ , the current flowing through S ₃ is zero, and the voltage rises slowly to V _C2 , realizing soft shutdown.

Phase 8 (t ₇ -t ₈ ) S ₁ and S ₄ are turned on, and the high voltage side will charge _Cr . After the parasitic capacitor voltage of S ₃ rises to V _C2 , the parasitic anti-parallel diode of S ₄ is turned on, and its drain-source voltage is 0. At this time, switch S ₄ is turned on, that is, zero-voltage turn-on is realized.

Stage 9 (t ₈ -t ₉ ) S ₁ and S ₄ are turned on, the high voltage side charges _Cr , the current _of Cr becomes positive, and S ₄ conducts forward.

Stage 10 (t ₉ -t ₁₀ ) S ₁ and S ₂ are in dead zone, the parasitic capacitance of S ₂ is discharged, and the parasitic capacitance of S ₁ is charged. After S ₁ is turned off, the resonant inductance L _r draws current from the junction of S ₁ and S ₂ . Due to the existence of the parasitic capacitance of S ₁ , the current flowing through S ₁ is zero, and the voltage rises slowly to V _C2 , realizing soft shutdown.

Stage 11 (t ₁₀ -t ₁₁ ) S ₂ and S ₄ are turned on, and C _r absorbs the energy of C ₂ . After the parasitic capacitor voltage of S ₁ rises to V _C1 , the parasitic anti-parallel diode of S ₂ is turned on, and its drain-source voltage is 0. At this time, switch S ₂ is turned on, that is, zero-voltage turn-on is realized.

In order to improve the voltage drop ratio, according to the converter topology in the above example, the number of stages of switched capacitor circuits is expanded; as shown in Figure 7, a non-isolated converter based on phase shift control includes n switched capacitor circuits And a transformer circuit, n switched capacitor circuits are cascaded in sequence, n=5 in this embodiment;

The switched capacitor circuit is composed of two switch tubes S ₁ ~ S ₂ , a high voltage capacitor C ₁ , a resonant capacitor C _r and a resonant inductor L _r ; among them, the input end of the switch tube S ₁ is connected to one end of the high voltage capacitor C ₁ And it is the first input end of the switched capacitor circuit, the output end of the switch tube _S1 is connected with the input end of the switch tube _S2 and one end of the resonant inductance L _r and is the second input end of the switched capacitor circuit, the switch tube _S2 The output end is connected to the other end of the high-voltage capacitor _C1 and is the first output end of the switched capacitor circuit, the other end of the resonant inductance L _r is connected to one end of the resonant capacitor C _r , and the other end of the resonant capacitor C _r is the switch capacitor circuit. second output terminal;

The first output end of the i-1th switched capacitor circuit is connected to the first input end of the i-th switched capacitor circuit, the second output end of the i-1th switched capacitor circuit is connected to the second input end of the i-th switched capacitor circuit, i is a natural number and 2≤i≤5;

Transformer circuit consists of two switch tubes S ₃ ~ S ₄ , an output capacitor C _out , a high-voltage capacitor C ₂ and a filter inductor L _f ; among them, the input end of the switch tube S ₃ and one end of the high-voltage capacitor C ₂ and The first output end of the fifth switched capacitor circuit is connected, the output end of the switch tube _S3 is connected with the input end of the switch tube _S4 , one end of the filter inductance _Lf is connected with the second output end of the fifth switched capacitor circuit, the switch tube S The output end of ₄ is connected to the other end of the high-voltage capacitor C ₂ ; the output capacitor C _out is connected between the other end of the filter inductor L _f and the other end of the high-voltage capacitor C ₂ .

The first input end of the first switched capacitor circuit and the other end of the high-voltage capacitor _C2 form a high-voltage side and are externally connected to a high-voltage power supply or high-voltage load, and the other end of the filter inductor _Lf and the other end of the high-voltage capacitor _C2 form a low-voltage side and are externally connected to a low voltage power supply or low voltage load;

The control terminal of the switch tube receives the control signal provided by the external device; the control signal received by the switch tube _S1 is complementary to the control signal received by the switch tube _S2 and there is a dead zone interval; the control signal received by the switch tube _S3 and the switch tube S ₄ The phases of the received control signals are complementary and there is a dead interval; the duty cycle of the control signal received by the switch _S1 is the same as that of the control signal received by the switch _S3 and there is a phase shift angle.

In this embodiment, since power-on and natural voltage equalization are required, C ₁ =C ₂ , the switching tubes are N-type MOS tubes, and the parameters of the switching tubes are basically the same.

Similar to the working principle of the variable current topology using a first-stage switched capacitor circuit combined with a variable voltage circuit as described above: when the phase shift angle is 0, the current of the resonant inductor L _r is zero, and no energy is transmitted between the high-voltage capacitors, and the system does not transmit energy;

When the phase shift angle is greater than 0 (S ₁ in the i-1 switched capacitor circuit is turned on prior to S 1 in the i switched capacitor circuit, and _{S 1 is} turned on prior to S ₃ in the fifth switched capacitor circuit), the i- 1 C ₁ in the switched capacitor circuit transmits energy to C 1 in the i-th switched capacitor circuit, C ₁ transmits energy to C ₂ in the fifth switched capacitor circuit, and the system transmits energy from the high voltage side to _the low voltage side; the capacitor C ₂ , the switch tube S ₃ and S ₄ , filter inductance L _f and output capacitor C _out form a BUCK circuit. Adjusting the phase shift angle can make the voltage of each high-voltage capacitor equal to 1/6 of the input voltage of the high-voltage side, and the output voltage of the low-voltage side is C ₂ The product of the upper voltage and the duty cycle D of the _S1 control signal, at this time, the low-voltage side load absorbs energy from _C2 and the fifth-stage resonant capacitor C _r , and _C2 and the fifth-stage resonant capacitor C r draw energy from the fifth-stage resonant capacitor C _r The high-voltage capacitor C ₁ and the fourth-stage resonant capacitor C _r absorb energy, and so on, the system transformation ratio is D/6;

When the phase shift angle is less than 0 (S ₁ in the i-1 switched capacitor circuit lags behind S 1 in the i switched capacitor circuit, and _{S 1 lags} behind S ₃ in the fifth switched capacitor circuit), the i switch C ₁ in the capacitor circuit transmits energy to C ₁ in the i-1th switched capacitor circuit, C ₂ transmits energy to C ₁ in the fifth switched capacitor circuit, and the system transmits energy from the low-voltage side to the high-voltage side; the capacitor C ₂ , the switch tube S ₃ and S ₄ and filter inductance L _f form a BOOST circuit (the output capacitor C _out is removed), the voltage on C ₂ is the input voltage of the low voltage side divided by the duty ratio D, and adjusting the phase shift angle can make each high voltage capacitor equal voltage, and the output voltage on the high-voltage side is 6 times the voltage of capacitor _C2 . At this time, the load on the high-voltage side absorbs energy from the first-stage high-voltage capacitor _C1 , and the power supply on the low-voltage side stores energy for _C2 and the fifth-stage resonant capacitor C _r , the fifth-stage high-voltage capacitor C ₁ and the fourth-stage resonant capacitor C _r absorb the energy on C ₂ and the fifth-stage resonant capacitor C _r , and so on, the system transformation ratio is 6/D.

Claims (6)

1. A non-isolated converter topology based on phase-shift control, characterized in that: it comprises a switched capacitor circuit and a transformer circuit; The switched capacitor circuit is composed of two switch tubes S ₁ -S ₂ , a high-voltage capacitor C ₁ , a resonant capacitor C _r and a resonant inductance L _r ; wherein, the input terminal of the switch tube S ₁ is connected to the high-voltage capacitor C ₁ One end of the switch tube _S1 is connected to the input end of the switch tube _S2 and one end of the resonant inductance L _r , the output end of the switch tube _S2 is connected to the other end of the high-voltage capacitor _C1 , and the resonant inductance L _r The other end is connected to one end of the resonant capacitor C _r , and the other end of the resonant capacitor C _r is connected to the transformer circuit; The voltage transformation circuit is composed of two switch tubes S ₃ -S ₄ , a high-voltage capacitor C ₂ and a filter inductor L _f ; wherein, the input end of the switch tube S ₃ and one end of the high-voltage capacitor C ₂ and the switched capacitor circuit The other end of the middle and high voltage capacitor C ₁ is connected, the output end of the switch tube S ₃ is connected with the input end of the switch tube S ₄ , one end of the filter inductance L _f is connected with the other end of the resonant capacitor C _r in the switched capacitor circuit, and the switch tube S ₄ The output terminal of the high voltage capacitor _C2 is connected to the other end; The control terminals of the switch tubes S ₁ -S ₄ all receive control signals provided by external equipment; wherein, the control signal received by the switch tube S ₁ is complementary to the control signal received by the switch tube S ₂ and there is a dead zone interval; the control signal received by switch tube _S3 is complementary to the control signal received by switch tube _S4 and there is a dead interval; the control signal received by switch tube _S1 and the duty ratio of the control signal received by switch tube _S3 The same and there is a phase shift angle. 2. The non-isolated converter topology based on phase-shift control according to claim 1, characterized in that: when the high-voltage side is used as the input and the low-voltage side is used as the output, the other end of the filter inductor L _f is connected to the high-voltage capacitor An output capacitor C _out is connected between the other ends of C ₂ . 3 . The non-isolated converter topology based on phase shift control according to claim 1 , wherein the switching tubes S ₁ -S 4 are all MOS tubes. ₄ . 4. A non-isolated converter based on phase-shift control, characterized in that: it includes n switched capacitor circuits and a transformer circuit, and n switched capacitor circuits are sequentially cascaded, and n is a natural number greater than 1; The switched capacitor circuit is composed of two switch tubes S ₁ -S ₂ , a high-voltage capacitor C ₁ , a resonant capacitor C _r and a resonant inductance L _r ; wherein, the input terminal of the switch tube S ₁ is connected to the high-voltage capacitor C ₁ One end is connected to the first input end of the switched capacitor circuit, the output end of the switch tube _S1 is connected to the input end of the switch tube _S2 and one end of the resonant inductance _Lr and is the second input end of the switched capacitor circuit, the switch tube The output terminal of S ₂ is connected with the other end of the high-voltage capacitor C ₁ and is the first output terminal of the switched capacitor circuit, the other end of the resonant inductor L _r is connected with one end of the resonant capacitor C _r , and the other end of the resonant capacitor C _r is a switch a second output terminal of the capacitor circuit; The first output end of the i-1th switched capacitor circuit is connected to the first input end of the i-th switched capacitor circuit, the second output end of the i-1th switched capacitor circuit is connected to the second input end of the i-th switched capacitor circuit, i is a natural number and 2≤i≤n; The voltage transformation circuit is composed of two switching tubes S ₃ -S ₄ , a high-voltage capacitor C ₂ and a filter inductance L _f ; wherein, the input end of the switching tube S ₃ is connected to one end of the high-voltage capacitor C ₂ and the nth switch The first output end of the capacitor circuit is connected, the output end of the switch tube _S3 is connected with the input end of the switch tube _S4 , one end of the filter inductance L _f is connected with the second output end of the nth switched capacitor circuit, and the output of the switch tube _S4 The end is connected with the other end of the high-voltage capacitor _C2 ; The control terminals of the switch tubes S ₁ -S ₄ all receive control signals provided by external equipment; wherein, the control signal received by the switch tube S ₁ is complementary to the control signal received by the switch tube S ₂ and there is a dead zone interval; the control signal received by switch tube _S3 is complementary to the control signal received by switch tube _S4 and there is a dead interval; the control signal received by switch tube _S1 and the duty ratio of the control signal received by switch tube _S3 The same and there is a phase shift angle. 5. The non-isolated converter based on phase-shift control according to claim 4, characterized in that: when the high-voltage side is used as the input and the low-voltage side is used as the output, the other end of the filter inductor L _f is connected to the high-voltage capacitor C An output capacitor C _out is connected between the other ends of ₂ . 6 . The non-isolated converter based on phase-shift control according to claim 4 , wherein the switching tubes S ₁ -S ₄ are all MOS tubes.