Zero-voltage turn-off zero-current turn-on high-gain Sepic converter

文档序号：1877985 发布日期：2021-11-23 浏览：4次中文

阅读说明：本技术 一种零电压关断零电流开通的高增益Sepic变换器 (Zero-voltage turn-off zero-current turn-on high-gain Sepic converter ) 是由邾玢鑫蓝海赵宇辉支树播杨楠李振华王凯宏于 2021-08-23 设计创作，主要内容包括：一种零电压关断零电流开通的高增益Sepic变换器,该变换器包括主电路、辅助电路；所述主电路包括Sepict变换器、至少一个外衣单元。所述Sepic变换器包含主电感L1、功率开关管S1、二极管D1、电容C1。所述辅助电路包括零电流电感Lr、辅助电感Ls、零电压电容Cr、二极管D2、D3、D4。本发明变换器实现了功率开关管的零电压关断和零电流导通,消除了功率开关管S1上的开关损耗,可以提高变换器的效率。(A high-gain Sepic converter with zero voltage turn-off and zero current turn-on comprises a main circuit and an auxiliary circuit; the main circuit comprises a Sepict transducer, at least one garment cell. The Sepic converter comprises a main inductor L1, a power switch tube S1, a diode D1 and a capacitor C1. The auxiliary circuit comprises a zero current inductor Lr, an auxiliary inductor Ls, a zero voltage capacitor Cr, diodes D2, D3 and D4. The converter realizes zero voltage turn-off and zero current conduction of the power switch tube, eliminates the switching loss on the power switch tube S1, and can improve the efficiency of the converter.)

1. A high-gain Sepic converter with zero voltage cut-off and zero current turn-on is characterized in that: the converter comprises a main circuit and an auxiliary circuit;

the main circuit comprises a Sepic converter and at least one coat unit;

the Sepic converter comprises an inductor L1, an inductor L2, a power switch tube S1, a capacitor C1, a diode D1 and a capacitor C2;

one end of an inductor L1 is connected with the anode of an input power supply, and the other end of an inductor L1 is respectively connected with the drain of a power switch tube S1 and one end of a capacitor C1; the source electrode of the power switch tube S1 is connected with the cathode of the input power supply; the cathode of the diode D1 is connected with one end of the capacitor C2, and the other end of the capacitor C2 is connected with the other end of the inductor L2, the drain of the power switch tube S1 and the cathode of the input power supply respectively;

said garment unit comprising a capacitor Cn1, a capacitor Cn2, an inductance Ln1, a diode Dn1, n being a natural number and n being equal to or greater than 1, the garment unit comprising five ports: port I, port II, port III, port IV and port V;

one end of a capacitor Cn1 is a port I, the other end of the capacitor Cn1 is respectively connected with one end of an inductor Ln1 and the anode of a diode Dn1, the other end of the inductor Ln1 is the port II, the cathode of the diode Dn1 is connected with one end of a capacitor Cn2, and the other end of the capacitor Cn2 is the port III; the anode of the diode Dn1 is a port (r), and the cathode of the diode Dn1 is a port (c);

the first port is connected to the anode of a diode D1 in the Sepic converter, the second port is connected to the cathode of a diode D1 in the Sepic converter, and the third port is connected to the cathode of an input power supply;

the auxiliary circuit comprises a zero current inductor Lr, an auxiliary inductor Ls, a zero voltage capacitor Cr, diodes D2, D3 and D4;

one end of a zero current inductor Lr is connected with the other end of a capacitor C1 in the Cuk converter and the anode of a diode D4;

the other end of the zero-current inductor Lr is respectively connected with one end of a capacitor C11 in the first garment unit, one end of an inductor L2 in the Sepic converter and the anode of a diode D1;

the cathode of the diode D2 is respectively connected with the anode of the input power supply and one end of the inductor L1;

the anode of the diode D2 is respectively connected with one end of the zero-voltage capacitor Cr and the cathode of the diode D3;

the anode of the diode D3 is connected with one end of an auxiliary inductor Ls, and the other end of the auxiliary inductor Ls is connected with the cathode of an input power supply;

the cathode of the diode D4 is connected with one end of the capacitor C2 in the Sepic converter.

2. The zero-voltage turn-off zero-current turn-on high-gain Sepic converter according to claim 1, characterized in that:

of the n garment units, the garment unit,

the port (r) of the second garment unit is connected to the port (r) in the first garment unit,

the port of the second garment unit is connected to the port in the first garment unit,

the port of the second coat unit is connected to the negative pole of the input power supply;

the port (r) of the third garment unit is connected to the port (r) in the second garment unit,

the port of the third garment unit is connected to the port in the second garment unit,

the port of the third coat unit is connected to the negative pole of the input power supply;

.... analogized in turn;

the port (r) of the nth garment unit is connected to the port (r) in the (n-1) th garment unit,

the port of the nth garment unit is connected to the port of the (n-1) th garment unit,

the port of the nth coat unit is connected to the negative pole of the input power supply.

3. The zero-voltage turn-off zero-current turn-on high-gain Sepic converter according to claim 1, characterized in that: the grid electrode of the power switch tube S1 is connected with the PWM controller.

4. The zero-voltage turn-off zero-current turn-on high-gain Sepic converter according to claim 1, characterized in that:

when the power switch tube S1 is conducted, the power switch tube S1 is conducted under the condition of zero current due to the action of the zero current inductor Lr, and the conduction loss of the power switch tube S1 is eliminated;

when the power switch tube S1 is turned off, the power switch tube S1 is turned off under the zero-voltage condition due to the action of the zero-voltage capacitor Cr, and the turn-off loss of the power switch tube S1 is eliminated.

5. A zero-voltage turn-off zero-current turn-on high-gain Sepic converter according to claim 1, 2, 3 or 4, characterized in that when a garment unit is included, the operation of the circuit is divided into 7 operation modes:

the first mode is as follows:

at the beginning of the mode, the main switch S1 is conducted under the ZCS condition because the magnitude and direction of the current on the zero-current inductor Lr and the inductor L1 cannot be suddenly changed; in this mode, the diodes D1, D3, D11 are turned on, the inductors L1, L11 and Ls are discharged, the capacitors C1, C2, C12 are charged, and the capacitor C11 is discharged; the diode D3 is conducted, and resonance begins between the auxiliary inductor Ls and the zero-voltage capacitor Cr; therefore, the Cr voltage falls in a sine curve, and the Ls current rises in a sine curve; in the working process, the main inductors L1 and Lr are linearly reduced, the current of the auxiliary inductor Ls is sinusoidally increased, and when the zero current inductor Lr is linearly reduced to iL1-iC1, the mode is ended;

mode two:

in this mode, the diodes D1 and D11 are turned off, the inductor L1 in the main circuit starts to charge, and the current increases linearly; the capacitors C1, C2, C12 start discharging and charge the inductors L11, Lr and the capacitor C11, respectively; the auxiliary inductor Ls and the zero-voltage capacitor Cr continue to resonate, when the voltage across the zero-voltage capacitor Cr in the auxiliary circuit reaches the negative input voltage-Vin, the diode D2 starts to conduct under ZVS condition, the Cr voltage is clamped at this level, and the mode ends;

mode three:

when the diode D2 starts to conduct under ZVS condition, mode three starts, and energy is stored due to the current flowing through the inductor Ls in the process of resonance with the zero-voltage capacitor Cr; when the voltage on Cr reaches a negative input voltage-Vin, the inductor Ls can continue to feed energy back to the input power supply through a diode D3; the working state of the components in the main circuit is the same as the previous mode; when the current of the inductor Ls is reduced to zero and the diode D2 is cut off, the mode ends;

and a fourth mode:

in the mode, the auxiliary circuit stops acting, and the circuit enters a normal working mode; the working state of the components in the main circuit is the same as the previous mode, and the load is continuously supplied with power by C22; when the power switch tube S1 is turned off, the mode ends;

a fifth mode:

in mode five, due to the existence of zero voltage Cr, the power switch tube S1 is turned off under ZVS; in this mode, the working state of the components in the main circuit is the same as that of the previous mode, and the load is continuously supplied with power by the C22; the current of the inductor L1 discharges Cr linearly, and when Vcr reaches zero, the current of the inductor L1 charges Cr linearly; when Vcr reaches Vc1-Vin, diode D4 begins to conduct under ZVS conditions, the Cr voltage is clamped at this level, and the mode ends;

a sixth mode:

when the diode D4 is turned on, the mode six begins, the diode D4 begins to be turned on under the ZVS condition, the currents of the inductors L1 and L11 linearly decrease, the capacitors C1, C11, C22 and the load are charged, the capacitor C2 is charged, the Lr current decreases to zero, and the mode ends;

a seventh mode: when the Lr current is reduced to zero, the mode seven begins, in which the diode D1 is turned on, the auxiliary circuit finishes working, the circuit returns to the normal mode, the current of the inductors L1 and L11 drops linearly, the capacitors C1, C2 and C12 and the load are charged, and the capacitor C11 discharges.

Technical Field

The invention relates to a direct current-direct current converter, in particular to a high-gain Sepic converter with zero voltage turn-off and zero current turn-on.

Background

In the existing switching power supply technology, the Sepic coat circuit well realizes high voltage gain, but in the high-gain DC/DC converter, in order to reduce the cost of the converter and improve the power density of the converter, the working frequency of a switching tube of the converter needs to be improved, but at present, the realization of high-frequency operation of the converter is still difficult. The main reason is that as the operating frequency of the converter is increased, the switching loss of the switching tube is correspondingly increased, which further reduces the operating efficiency of the converter and increases the heat productivity. In addition, the heat sink volume and weight also increase. The increase in switching frequency mainly causes the following two problems:

(1) the problem of switching losses: in the switching process of the power switch tube, the voltage and the current of the power switch tube are not zero, and an overlapping area appears, and the area is the switching loss of the power switch tube. The switching loss and the switching frequency have a linear relation, and the switching loss can be obviously increased after the switching frequency is increased.

(2) Emi (electromagnetic interference) electromagnetic interference effects: when the converter operates at high frequency, the voltage and current change faster, the waveform will overshoot significantly, the switching tubes will have to produce higher du/dt and di/dt, which will have an impact on the power supply itself and surrounding electronics, and switching noise, and EMI problems will become more severe after further increase of the switching frequency.

Aiming at the problems of the existing high-gain DC/DC converter, the soft switching technology is adopted, so that the switching loss can be reduced to zero theoretically, and meanwhile, the interference of EMI problems to electronic devices can be reduced.

Disclosure of Invention

The invention provides a high-gain Sepic converter for zero-voltage turn-off and zero-current turn-on, which enables a power switch tube to realize zero-voltage turn-off and zero-current turn-on through an auxiliary circuit and reduces the switching loss on the power switch tube in the circuit.

The technical scheme adopted by the invention is as follows:

a high-gain Sepic converter with zero voltage turn-off and zero current turn-on comprises a main circuit and an auxiliary circuit;