A control method and device for a step-down circuit

A technology of step-down circuit and control method, applied in output power conversion devices, control/regulation systems, photovoltaic power generation, etc. Small voltage and power fluctuations, suppressing output voltage fluctuations, and ensuring stable transition effects

CN104242645BActive Publication Date: 2017-02-15SUNGROW POWER SUPPLY CO LTD
5 Cites 0 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2017-02-15

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The invention provides a method and a device for controlling step-down circuits. The method includes converting states of switch tubes of step-down type conversion circuits into normally open states under the control when working state conversion is carried out on bypass circuits by the step-down type conversion circuits, keeping the switch tubes of the step-down type conversion circuits in the normally open states for first preset time, then converting the states of the switch tubes into shutdown states, and converting states of switch tubes of the bypass circuits into normally open states under the control when the switch tubes of the step-down type conversion circuits keep in the normally open states; converting the states of the switch tubes of the step-down type conversion circuits into the normally open states under the control when working state conversion is carried out on the step-down type conversion circuits by the bypass circuits, keeping the switch tubes of the step-down type conversion circuits in the normally open states for second preset time, then converting the states of the switch tubes of the step-down type conversion circuits into PWM (pulse width modulation) working states, and converting the states of the switch tubes of the bypass circuits into shutdown states under the control when the switch tubes of the step-down type conversion circuits keep in the normally open states. The method and the device have the advantage that working states can be converted between the step-down type conversion circuits and the bypass circuits by the aid of the method and the device under the condition of low voltage and power fluctuation.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention relates to the field of grid-connected inverters, in particular to a control method and device for a step-down circuit. Background technique

[0002] In the field of photovoltaic power generation, the grid-connected inverter usually adopts a two-stage structure of DC / DC converter and DC / AC converter, in which the DC / DC converter completes the conversion of DC voltage, and the DC / AC converter converts the DC / DC The DC output from the converter is converted to AC at the desired frequency. Among them, the DC / DC converter can adopt a step-up conversion circuit, a step-down conversion circuit, or a conversion circuit with both step-up and step-down functions. In order to improve efficiency, the DC / DC converter usually adopts a bypass structure, that is, Together with the bypass circuit connected in parallel, it forms a step-down circuit.

[0003] In the actual working process, the step-down conversion circuit and the bypass circuit will cont...

Examples

Embodiment Construction

[0048] In the field of photovoltaic power generation, the grid-connected inverter usually adopts a two-stage structure of DC / DC converter and DC / AC converter, in which the DC / DC converter completes the conversion of DC voltage, and the DC / AC converter converts the DC / DC The DC output from the converter is converted to AC at the desired frequency. Among them, the DC / DC converter can adopt a step-up conversion circuit, a step-down conversion circuit, or a conversion circuit with both step-up and step-down functions. In order to improve efficiency, the DC / DC converter usually adopts a bypass structure, that is, Together with the bypass circuit connected in parallel, it forms a step-down circuit.

[0049] In the actual working process, the step-down conversion circuit and the bypass circuit will continuously switch working states according to actual needs. However, in the prior art, voltage or power fluctuations at the input side are easily caused when such a working state is swi...