CN104158404A - Controllable two-way DC-DC converter and control method thereof - Google Patents

Abstract

The invention discloses a controllable two-way DC-DC (Direct Current-Direct Current) converter and a control method thereof. The two-way DC-DC converter comprises a main circuit and a control circuit, wherein the main circuit is connected with the control circuit. The control method of the two-way DC-DC converter is divided into two processes namely a boost conversion process and a buck conversion process; in the boost conversion process, a sampling voltage signal is subjected to A/D (Analog-to-Digital) conversion, the size of a duty ratio is adjusted through an incremental digital PI algorithm according to a set voltage value, and the voltage of an output end is controlled; in the buck conversion process, a sampling current signal is subjected to A/D conversion, the size of the duty ratio is adjusted through the incremental digital PI algorithm according to a set current value, and the current of the output end is controlled. The two-way DC-DC converter is simple, practical, high in efficiency, safe and reliable to operate, convenient to use and low in cost.

Description

A kind of controlled bidirectional DC-DC converter and control method thereof

Technical field

The invention belongs to converters technical field, be specifically related to a kind of controlled bidirectional DC-DC converter and control method thereof.

Background technology

In fields such as Aero-Space, solar power generation, wind power generation, electric automobile, uninterrupted power supplys, generally adopt bidirectional DC-DC converter, bidirectional DC-DC converter can be realized the two-way flow of energy, is specially adapted to the occasion that need to discharge and recharge storage battery.Existing bidirectional DC-DC converter topological structure is complicated, energy transport link is more, the components and parts of use are more, efficiency is high, cost is high.

Summary of the invention

In order to overcome the shortcoming of above-mentioned prior art, the object of the present invention is to provide a kind of controlled bidirectional DC-DC converter and control method thereof, simple and practical, efficiency is high, safe and reliable to operation, easy to use, and cost is low.

In order to achieve the above object, the technical scheme that the present invention takes is:

A controlled bidirectional DC-DC converter, comprises main circuit and control circuit, and main circuit is connected with control circuit;

Described main circuit comprises transformer T, inductance L, capacitor C, diode VD1, diode VD2, diode VD3, diode VD4, field effect transistor V1, field effect transistor V2, field effect transistor V3, anodic bonding transformer T armature winding one end of diode VD1 and the drain electrode of field effect transistor V1, negative electrode connects source electrode and the input Ui-of field effect transistor V1, the grid of field effect transistor V1 connects the drive circuit of control circuit, the anodic bonding input Ui-of diode VD4, one end of negative electrode connection transformer T armature winding, the other end of transformer T armature winding connects input Ui+, the source electrode of the anodic bonding field effect transistor V2 of diode VD2, the anode of diode VD3, capacitor C one end, output Uo-, the negative electrode of diode VD2 connects drain electrode and transformer T secondary winding one end of field effect transistor V2, and the grid of field effect transistor V2 connects the drive circuit of control circuit, and the negative electrode of diode VD3 connects the drain electrode of field effect transistor V3, the other end of transformer T secondary winding, one end of inductance L, the other end of inductance L connects the other end of capacitor C, input Uo+,

Described control circuit comprises drive circuit, electric current and voltage sampling and controls IC, control IC one end and connect electric current and voltage sampling, the other end connects drive circuit, and the electric current and voltage sampling other end connects the output of main circuit, and the drive circuit other end connects the field effect transistor in main circuit.

The control method of described bidirectional DC-DC converter, comprises the following steps:

Step 1): start, preparation powers on;

Step 2): initialization Target Board, carries out initialization to hardware;

Step 3): buck is prepared;

Step 4): be divided into two processes, boosting inverter and decompression transformation;

In boosting inverter, sampled voltage signal is carried out to A/D conversion, according to the magnitude of voltage of setting, by Increment Type Digital Hydraulic PI algorithm, regulate the size of duty ratio, control output end voltage;

In decompression transformation, sample rate current signal is carried out to A/D conversion, according to the current value of setting, by Increment Type Digital Hydraulic PI algorithm, regulate the size of duty ratio, control output end electric current.

The beneficial effect of tool of the present invention: simple and practical, efficiency is high, safe and reliable to operation, easy to use, and cost is low.

Accompanying drawing explanation

Fig. 1 is the circuit diagram of bidirectional DC-DC converter of the present invention.

Fig. 2 is the flow chart of bidirectional DC-DC converter control method of the present invention.

Embodiment

Below in conjunction with Figure of description, the present invention is further described.

With reference to Fig. 1, a kind of controlled bidirectional DC-DC converter, comprises main circuit and control circuit, and main circuit is connected with control circuit;

Described main circuit comprises transformer T, inductance L, capacitor C, diode VD1, diode VD2, diode VD3, diode VD4, field effect transistor V1, field effect transistor V2, field effect transistor V3, anodic bonding transformer T armature winding one end of diode VD1 and the drain electrode of field effect transistor V1, negative electrode connects source electrode and the input Ui-of field effect transistor V1, the grid of field effect transistor V1 connects the drive circuit of control circuit, the anodic bonding input Ui-of diode VD4, one end of negative electrode connection transformer T armature winding, the other end of transformer T armature winding connects input Ui+, the source electrode of the anodic bonding field effect transistor V2 of diode VD2, the anode of diode VD3, capacitor C one end, output Uo-, the negative electrode of diode VD2 connects drain electrode and transformer T secondary winding one end of field effect transistor V2, and the grid of field effect transistor V2 connects the drive circuit of control circuit, and the negative electrode of diode VD3 connects the drain electrode of field effect transistor V3, the other end of transformer T secondary winding, one end of inductance L, the other end of inductance L connects the other end of capacitor C, input Uo+,

Described control circuit comprises drive circuit, electric current and voltage sampling and controls IC, control IC one end and connect electric current and voltage sampling, the other end connects drive circuit, and the electric current and voltage sampling other end connects the output of main circuit, and the drive circuit other end connects the field effect transistor in main circuit.

With reference to Fig. 2, the control method of described bidirectional DC-DC converter, comprises the following steps:

Step 1): start, preparation powers on;

Step 2): initialization Target Board, carries out initialization to hardware;

Step 3): buck is prepared;

Step 4): be divided into two processes, boosting inverter and decompression transformation;

In boosting inverter, sampled voltage signal is carried out to A/D conversion, according to the magnitude of voltage of setting, by Increment Type Digital Hydraulic PI algorithm, regulate the size of duty ratio, control output end voltage;

In decompression transformation, sample rate current signal is carried out to A/D conversion, according to the current value of setting, by Increment Type Digital Hydraulic PI algorithm, regulate the size of duty ratio, control output end electric current.

The operation principle of bidirectional DC-DC converter of the present invention is:

During forward work, first stage, field effect transistor V1 was controlled circuit triggers conducting, input terminal voltage is added on armature winding, iron core magnetization, iron core magnetic flux increases, the increase of starting from scratch of the exciting current of transformer, now, field effect transistor V2 is controlled circuit triggers conducting, field effect transistor V3 cut-off, and filter inductance electric current is linear to be increased; Second stage, field effect transistor V1 is in off state, in primary, secondary winding, all no current passes through, now transformer resets by reset winding, exciting current feeds back to input through diode VD4, now, diode VD2 and VD3 all turn-off, and filter inductance electric current is by diode VD3 afterflow; Phase III, field effect transistor V1 is still in off state, and field effect transistor V3 is controlled circuit triggers conducting, and conduction loss is greatly reduced, filter inductance electric current continues the afterflow through field effect transistor V3, and this stage will last till that field effect transistor V3 finishes while being triggered shutoff; Fourth stage, field effect transistor V3 turn-offs, but still conducting afterflow of diode VD3 does not have electric current in transformer, and this stage, so far, a work period of forward work finished until field effect transistor V1 finishes while being controlled circuit triggers conducting.

During reverse operation, first stage: field effect transistor V3 is controlled circuit triggers conducting, and field effect transistor V2 turn-offs, output electric discharge, and electric current flows through inductance L, and electric current is linear to be increased, and reaches maximum, and electric energy is stored in L with magnetic energy form; Second stage, field effect transistor V2 is controlled circuit triggers conducting, and field effect transistor V3 turn-offs, and the magnetic energy in inductance L is converted into electric energy, and to outlet side electric discharge, so far, a work period of reverse operation finishes together with output.

The present invention is safe and reliable, has good power supply characteristic, and adopts digital control.

Claims (2)

1. a controlled bidirectional DC-DC converter, comprises main circuit and control circuit, and main circuit is connected with control circuit, it is characterized in that:

Described main circuit comprises transformer T, inductance L, capacitor C, diode VD1, diode VD2, diode VD3, diode VD4, field effect transistor V1, field effect transistor V2, field effect transistor V3, anodic bonding transformer T armature winding one end of diode VD1 and the drain electrode of field effect transistor V1, negative electrode connects source electrode and the input Ui-of field effect transistor V1, the grid of field effect transistor V1 connects the drive circuit of control circuit, the anodic bonding input Ui-of diode VD4, one end of negative electrode connection transformer T armature winding, the other end of transformer T armature winding connects input Ui+, the source electrode of the anodic bonding field effect transistor V2 of diode VD2, the anode of diode VD3, capacitor C one end, output Uo-, the negative electrode of diode VD2 connects drain electrode and transformer T secondary winding one end of field effect transistor V2, and the grid of field effect transistor V2 connects the drive circuit of control circuit, and the negative electrode of diode VD3 connects the drain electrode of field effect transistor V3, the other end of transformer T secondary winding, one end of inductance L, the other end of inductance L connects the other end of capacitor C, input Uo+,

Described control circuit comprises drive circuit, electric current and voltage sampling and controls IC, control IC one end and connect electric current and voltage sampling, the other end connects drive circuit, and the electric current and voltage sampling other end connects the output of main circuit, and the drive circuit other end connects the field effect transistor in main circuit.

2. the control method of bidirectional DC-DC converter according to claim 1, is characterized in that, comprises the following steps:

Step 1): start, preparation powers on;

Step 2): initialization Target Board, carries out initialization to hardware;

Step 3): buck is prepared;

Step 4): be divided into two processes, boosting inverter and decompression transformation;

In boosting inverter, sampled voltage signal is carried out to A/D conversion, according to the magnitude of voltage of setting, by Increment Type Digital Hydraulic PI algorithm, regulate the size of duty ratio, control output end voltage;

In decompression transformation, sample rate current signal is carried out to A/D conversion, according to the current value of setting, by Increment Type Digital Hydraulic PI algorithm, regulate the size of duty ratio, control output end electric current.