CN101521458A - Topological structure for L-shaped booster converter - Google Patents

Abstract

The invention discloses _a topological structure of an L-type boost converter, which is characterized in that the horizontal axis of the L-type converter is formed by connecting controllable switches S ₁₁ , S ₂₁ ... S _k1 in series with k devices; A total of k capacitors C ₂ ... C _k are connected in series to form the vertical axis of the L-shaped converter; one end of the controllable switch S _k1 is connected to the positive pole of the power supply through the inductance L _A , and there are control channels between the negative pole of the power supply and each node of the horizontal axis Controlled switches S ₁₃ , S ₂₃ ... S _k3 branch; the node between the capacitors C _i and C _(i+1) and the node between the controllable switches S _i1 and S _(i+1)1 on the horizontal axis The space is a branch composed of controllable switches S ₁₂ , S ₂₂ ... S _k2 , one end of the capacitor C _k is connected to the node of the controllable switch S _k1 and the inductor L _A through a diode, and the cathode of the diode is connected to the capacitor C _k ; i=1, 2...k-1, k is a positive integer, and k is greater than or equal to 1; the converter is expanded by expanding the horizontal and vertical axes and switch branches of the T-shaped structure.

Description

Topology of L-type boost converter

technical field

The invention relates to a circuit topological structure of a step-up converter, in particular to a topological structure of a DC-DC type step-up converter using a single inductor.

Background technique

In the traditional DC-DC step-up circuit, when the step-up ratio is relatively high, a converter with a transformer structure or a multi-stage step-up structure is often used. Due to the high boost multiple, the control accuracy is difficult to be guaranteed, and the series structure of the system leads to low reliability and stability of the system.

Contents of the invention

The technical problem to be solved by the present invention is: to solve the control accuracy when the boost multiple is high, and propose a topology that adopts multiple output capacitors in series and performs boost control on each output cascaded capacitor to achieve high performance boost conversion.

In order to achieve the above object, technical scheme of the present invention is as follows:

A topological structure of an L-type boost converter, the horizontal axis of the L-type converter is formed by connecting k switching devices in series; the vertical axis of the L-type converter is formed by connecting k capacitors in series; the leftmost switch of the horizontal axis is connected by an inductor and The high potential end of the DC input power supply is connected, and the low potential end of the DC input power supply is connected to each node on the horizontal axis by a switch branch; the node between two adjacent controllable switches on the horizontal axis and the connection between two adjacent capacitors on the vertical axis The nodes are connected by a unidirectional switch branch; the converter can be expanded by expanding the horizontal and vertical axes of the L-shaped structure, the unidirectional rectification branch, and the unidirectional controllable switch branch, and k is a positive integer greater than or equal to 1.

Beneficial effects of the present invention:

Compared with the traditional DC-DC boost converter, the L-type boost converter disclosed in the present invention adopts a single-inductance structure to independently charge the capacitors on each series output side. , has high control precision; at the same time, it also overcomes the problems of insufficient stability and reliability of the multi-stage series system.

Description of drawings

FIG. 1 is a topological structure diagram of an L-type boost converter proposed by the present invention.

Figure 2(a) is a MOSFET equivalent example diagram of a controllable switch.

Figure 2(b) is an equivalent example diagram of an IGBT with a controllable switch.

Detailed ways

The present invention will be further described in conjunction with accompanying drawing:

Figure 1 is a topology diagram of an L-type boost converter. A total of k devices of the controllable switches S ₁₁ , S ₂₁ ... S _k1 are connected in series to form the horizontal axis of the L-shaped converter; a total of k capacitors of the capacitors C ₁ , C ₂ ... C _k are connected in series to form the vertical axis of the L-shaped converter axis; one end of the switch S _k1 is connected to the positive pole of the power supply through the inductor L _A , and there is a branch composed of controllable switches S ₁₃ , S ₂₃ ... S _k3 between the negative pole of the power supply and each node of the horizontal axis; the capacitor C _i and _{The controllable switch} S _12. A branch composed of S ₂₂ ... S _k2 , one end of the capacitor C _k is connected to the node of S _k1 and the inductor L _A through a diode, and the cathode of the diode is connected to the capacitor C _k ; k is a positive integer, and k≥1 ; By expanding the horizontal and vertical axes and the switch branch of the L-shaped structure, the converter can be expanded. The load _RL represents the load of the system, which has various forms and properties.

The controllable switches S _k1 , S _k2 , S _k3 , and the capacitor C _k constitute the extended unit group of the L-type boost converter. When the circuit is expanded according to the above connection method, the number of stages of the converter will be increased.

The capacitors C ₁ , C _{2 .} The discharge state is the same as that of the traditional boost converter, and will not be described here. The following is a brief description of the time-sharing charging of each power supply.

The charging process of each capacitor can be divided into the stage of energy storage by the inductor and the stage of energy transfer from the inductor to the capacitor. Taking the capacitor C _n (n=1, 2...k) shown in Figure 1 as an example, its energy storage and During the energy transfer process, the switch S _j1 (j<n) is in the off state, the switches S _j1 (j>n), S _(n-1)2 , and S _n3 are in the on state, and work is performed by switching the switch state of S _n1 , the detailed process is as follows.

Inductive energy storage stage: when the controllable switch S _n1 is turned on, the controllable switches S _k1 , S _(k-1)1 ... S _n1 , S _n2 are in the on state. At this time, the power supply V and the inductor L _A , The controllable switches S _k1 , S _(k-1)1 ... S _n1 , S _n2 , S _n3 form a loop, the DC input power supplies energy to the inductor, and the current on the inductor increases continuously.

The stage of energy transfer to the capacitor: the state of the controllable switch S _n1 is switched to cut-off, at this time the power supply V, the inductor L _A , the anti-coupled diode of the controllable switch S _n2 , the capacitor C _n , and the controllable switch S _(n-1)2 , S _n3 form a loop, at this time the energy of the DC input power supply and the inductance is transferred to the capacitor C _n .

Figure 2(a) is a MOSFET equivalent example diagram of a controllable switch. Figure 2(b) is an equivalent example diagram of an IGBT with a controllable switch. The switches in the topology can choose a variety of controllable switches or switch topologies, and only two examples are given here.

Claims (3)

1. A topological structure of an L-type boost converter, characterized in that: through controllable switches S ₁₁ , S ₂₁ ... S _k1 , a total of k devices are connected in series to form the horizontal axis of the L-type converter; through capacitors C ₁ , A total of k capacitors C ₂ ... C _k are connected in series to form the vertical axis of the L-shaped converter; one end of the controllable switch S _k1 is connected to the positive pole of the power supply through the inductance L _A , and there are control channels between the negative pole of the power supply and each node of the horizontal axis Controlled switches S ₁₃ , S ₂₃ ... S _k3 branch circuit; capacitance C _i and C _(i+1) , i=1, 2 ... k-1, the node between the controllable switch S on the horizontal axis Between the nodes of _i1 and S _(i+1)1 is a branch composed of controllable switches S ₁₂ , S ₂₂ ... S _k2 , one end of the capacitor C _k passes through the diode, the controllable switch S _k1 and the inductor L _A The nodes are connected, and the cathode terminal of the diode is connected with a capacitor C _k ; k is a positive integer, and k≥1; the converter is expanded by extending the horizontal and vertical axes and the switch branch of the T-shaped structure. 2. The topological structure of the L-type boost converter according to claim 1, characterized in that: the controllable switches S _k1 , S _k2 , S _k3 , and the capacitor C _k constitute the extended unit group of the L-type boost converter, When expanding the circuit according to the above-mentioned connection method, the number of stages of the converter will be increased. 3. The topology structure of the L-type boost converter according to claim 1, characterized in that: the controllable switches S ₁₁ , S ₂₁ ... S _k1 , S ₁₂ , S ₂₂ ... S _(k-1)2 Fully controlled electronic switches or switch components with anti-parallel diodes are adopted; controllable switches S ₁₃ , S ₂₃ ... S _k3 adopt fully controlled electronic switches or switch components with reverse blocking.

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