CN209170228U - A kind of novel expansible Sepic DC-DC converter - Google Patents

Abstract

The utility model proposes a kind of novel expansible Sepic DC-DC converters.Mentioned converter is made of basic Speic converter and several mentioned expanding elements.Mentioned expanding element is made of an inductance, two capacitors and a diode, and the adjusting to converter input and output gain and switching device voltage stress can be realized in the number by adjusting mentioned expanding element.Mentioned converter has the advantages such as control and driving circuit are simple, input and output voltage adjustable range is wide, switching device voltage stress is low, is more suited to the biggish application of change range of input voltage.

Description

A Novel Scalable Sepic DC-DC Converter

technical field

The utility model relates to a step-up and step-down DC/DC converter, in particular to a novel expandable Sepic DC-DC converter.

Background technique

Common non-isolated buck-boost DC-DC converters include Buck-Boost, Cuk, Sepic and Zeta circuits. The input-output voltage relationship of these converters can either be greater than 1 (boost) or less than 1 (buck), and are widely used in many industrial applications. However, due to the influence of the parasitic parameters of components and circuits, the boosting capability of these converters is greatly restricted. Most of the solutions are based on Boost circuits, so they can only achieve boost, not buck, and are difficult to adapt to applications with large input voltage changes. Therefore, it is of great significance to study a new type of buck-boost DC-DC converter that can achieve high-gain boost and step-down.

SUMMARY OF THE INVENTION

In order to solve the problems of high voltage and current stress of devices and low input and output gain existing in the existing non-isolated buck-boost DC-DC converters, the present utility model proposes a novel scalable Sepic DC-DC converter based on the basic Sepic circuit. device.

The technical scheme adopted by the utility model is:

A novel scalable Sepic DC-DC converter, which includes a DC input source, a load R _L , a basic Specic converter, and n expansion units. in:

The basic Speic converter includes two inductors L ₁ , L ₂ , two capacitors C ₁ , C ₂ , a power switch S ₁ , and a diode D ₁ . The connection form is as follows: the left end _of the inductor L1 is connected to the positive electrode of the input power supply, the right end is connected to the drain of the power switch S1 and the left end of the capacitor _C1 , and the right end _of the capacitor _C1 is connected to the upper end of the inductor _L2 and the anode _of the diode D1. , the cathode _of the diode D1 is connected to the upper end of the capacitor _C2 , the source _of the power switch S1, the lower end of the inductor _L2 and the lower end of the capacitor _C2 are connected to the negative electrode of the input power supply.

The components and internal connection forms of the n expansion units are the same, and the i-th expansion unit is taken as an example for illustration, which includes: an inductor L _i1 , a diode D _i1 , and two capacitors C _i1 and C _i2 . The right end of the capacitor C _i1 is connected to the upper end of the inductor L _i1 and the anode of the diode D _i1 , and the cathode of the diode D _i1 is connected to the upper end of the capacitor C _i2 .

The connection form between each expansion unit is as follows (1<i≤n): the right end of the capacitor C _(i-1)1 , the upper end of the inductor L _(i-1)1 and the diode D ₍ The intersection point where the anode of _i-1)1 is connected is connected to the left end of the capacitor C _i1 in the i-th expansion unit, and the cathode of the diode D _(i-1)1 in the i-1-th expansion unit is connected to the capacitor C _(i-1) The intersection point where the upper end of ₂ is connected is connected to the lower end of the inductance L _i1 in the i-th expansion unit, and the lower end of the capacitor C _(i-1)2 in the i-1-th expansion unit is connected with the i-th expansion unit. The lower end of the capacitor C _i2 and the negative pole of the input power supply.

The connection relationship between the first extension unit and the basic Speic converter is as follows: the right end of the capacitor C ₁ in the basic Speic converter is connected to the upper end of the inductor L ₂ and the anode of the diode D ₁ The intersection point connected with the capacitor in the first extension unit The left end of C ₁₁ is connected, and the intersection of the cathode of diode D ₁ in the basic Speic converter and the upper end of capacitor C ₂ is connected to the lower end of inductor L ₁₁ in the first expansion unit.

Both ends of the load _RL are connected to both ends of the capacitor C _n2 in the nth expansion unit.

_The gate of the power switch S1 is connected to its controller, and its duty cycle can vary from 0 to 1.

The utility model is a novel scalable Sepic DC-DC converter, and the technical effects are as follows:

1. The input and output gain is high and adjustable, and the voltage stress of the switching device is low. Where (when the current of inductor L ₁ is continuously conducting):

The ratio of output voltage to input voltage is:

The voltage stress of the switch tube is:

Where D is the duty cycle, u _in is the input voltage, u _o is the output voltage, u _s is the voltage stress of the power switch, and n is the number of expansion units.

2. Only one power switch is included, and the control strategy and drive circuit are simple.

Description of drawings

Fig. 1 is the circuit principle diagram of the present utility model.

FIG. 2 is a circuit topology diagram when the number of expansion units of the present invention is 1. FIG.

Figure 3 is a circuit topology diagram of a basic Sepic converter.

FIG. 4 is a comparison diagram of the input and output gain of the utility model when the number of expansion units is 1 and the input and output gain of the traditional Sepic converter.

Detailed ways

The present utility model will be described in further detail below in conjunction with the accompanying drawings.

as shown in picture 2:

A Sepic DC-DC converter with expandable unit includes a DC input source, a load R _L , a basic Speic converter, and an expansion unit. in:

The basic Speic converter includes two inductors L ₁ , L ₂ , two capacitors C ₁ , C ₂ , a power switch S ₁ , and a diode D ₁ . The connection form is as follows: the left end _of the inductor L1 is connected to the positive electrode of the input power supply, the right end is connected to the drain of the power switch S1 and the left end of the capacitor _C1 , and the right end _of the capacitor _C1 is connected to the upper end of the inductor _L2 and the anode _of the diode D1. , the cathode _of the diode D1 is connected to the upper end of the capacitor _C2 , the source _of the power switch S1, the lower end of the inductor _L2 and the lower end of the capacitor _C2 are connected to the negative electrode of the input power supply.

The expansion unit contains: an inductor L ₁₁ , a diode D ₁₁ , and two capacitors C ₁₁ and C ₁₂ . The right end of the capacitor _C11 is connected to the upper end of the inductor _L11 and the anode of the diode _D11 , the cathode of the diode _D11 is connected to the upper end _of the capacitor C12, and the lower end _of the capacitor C12 is connected to the negative electrode of the input power supply

The connection relationship between the extension unit and the basic Speic converter is as follows: the right end of the capacitor _C1 in the basic _Speic converter is connected with the upper end of the inductor L2 and the anode of the diode D1 _The intersection point is connected with the left end of the capacitor _C11 in the extension unit, The intersection point where the cathode of diode D ₁ in the basic Speic converter is connected to the upper end of capacitor C ₂ is connected to the lower end of inductor L ₁₁ in the extension unit.

Both ends of the load _RL are connected to both ends _of the capacitor C12 in the expansion unit.

_The gate of the power switch S1 is connected to its controller, and its duty cycle can vary from 0 to 1.

When the current of the inductor L ₁ is continuously turned on, the circuit can be divided into two working states according to the different power switch states:

(1) The power switch S ₁ is turned on, and the diodes D ₁ and D ₁₁ are both turned off. At this time, the inductors L ₁ , L ₂ , L ₁₁ , and the capacitor C ₁₁ are charged, and the capacitors C ₁ , C ₂ , and C ₁₂ are discharged; the inductor L ₁ , L ₂ , L ₁₁ terminal voltage is shown in the following formula:

(2) The power switch S ₁ is turned off, and the diodes D ₁ and D ₁₁ are both turned on. At this time, the inductors L ₁ , L ₂ , L ₁₁ , and the capacitor C ₁₁ are discharged, and the capacitors C ₁ , C ₂ , and C ₁₂ are charged; the inductor L ₁ , L ₂ , L ₁₁ terminal voltage is shown in the following formula:

The above embodiments of the present invention are only examples for illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, changes and modifications in other different forms can also be made on the basis of the above description. Not all implementations can be exhaustive here. Anything belonging to the technical solutions of the present utility model, the obvious changes or changes derived from it are still within the protection scope of the present utility model.

Claims (1)

1. a novel scalable Sepic DC-DC converter, it is characterized in that: this converter comprises a direct current input source, a load R _L , a basic Specic converter, n expansion units; Wherein: The basic Speic converter includes two inductors L ₁ , L ₂ , two capacitors C ₁ , C ₂ , a power switch S ₁ , and a diode D ₁ ; its connection form is as follows: the left end of the inductor L ₁ is connected to the positive pole of the input power supply, The right end is connected to the drain of the power switch S1 and the left end of the capacitor _C1 , the right end _of the capacitor _C1 is connected to the upper end of the inductor L2 and the anode _of the diode D1, the cathode _of the diode _D1 is connected to the upper end of the capacitor _C2 , the power switch _The source of S1, the lower end of the inductor L2 and the lower end of the capacitor _C2 are connected to the negative electrode of the input power supply _; The components and internal connection forms of the n expansion units are all the same. Taking the i-th expansion unit as an example, it contains: an inductor L _i1 , a diode D _i1 , and two capacitors C _i1 and C _i2 ; the capacitor C _i1 The right end is connected with the upper end of the inductor L _i1 and the anode of the diode D _i1 , and the cathode of the diode D _i1 is connected with the upper end of the capacitor C _i2 ; The connection form between each expansion unit is as follows, 1<i≤n,: the right end of the capacitor C _(i-1)1 , the upper end of the inductor L _(i-1)1 and the diode D ₍ The intersection point where the anode of _i-1)1 is connected is connected to the left end of the capacitor C _i1 in the i-th expansion unit, and the cathode of the diode D _(i-1)1 in the i-1-th expansion unit is connected to the capacitor C _(i-1) The intersection point where the upper end of ₂ is connected is connected to the lower end of the inductance L _i1 in the i-th expansion unit, and the lower end of the capacitor C _(i-1)2 in the i-1-th expansion unit is connected with the i-th expansion unit. The lower end of the capacitor C _i2 And the negative pole of the input power supply is connected; The connection relationship between the first extension unit and the basic Speic converter is as follows: the right end of the capacitor C ₁ in the basic Speic converter is connected to the upper end of the inductor L ₂ and the anode of the diode D ₁ The intersection point connected with the capacitor in the first extension unit The left end of C11 is connected, and the intersection point where the cathode _of diode D1 in the basic _Speic converter is connected with the upper end of capacitor _C2 is connected with the lower end of inductor _L11 in the first expansion unit; Both ends of the load _RL are connected to both ends of the capacitor C _n2 in the nth expansion unit.