CN114337219A

CN114337219A - Method for reducing starting-up peak reversal of transistor in push-pull circuit and mobile power supply

Info

Publication number: CN114337219A
Application number: CN202111599102.6A
Authority: CN
Inventors: 陈聪鹏; 黄子鸿; 王刚; 王志军
Original assignee: Xiamen Haisuo Technology Co ltd
Current assignee: Xiamen Haisuo Technology Co ltd
Priority date: 2021-12-24
Filing date: 2021-12-24
Publication date: 2022-04-12

Abstract

The invention belongs to the technical field of power supplies, and particularly relates to a method for reducing starting-up peak reversal of a transistor in a push-pull circuit and a mobile power supply. The method is performed by a processing unit controlling transistor switches in a push-pull circuit, comprising: step S1, when the electronic device is turned on, the duty ratio of the transistor driving signal is gradually increased to a set duty ratio, where the set duty ratio is the duty ratio of the driving signal when the push-pull circuit normally works. The processing unit is used for controlling the duty ratio of the transistor driving signal to be gradually increased, so that the bus voltage is gradually increased to a set voltage, namely a buffer process is given to the bus capacitor, and the phenomenon that the transistor peak-reversal exceeds the standard due to the fact that a larger current is generated due to the characteristics of the electrolytic capacitor at the moment of starting up the machine is avoided.

Description

Method for reducing starting-up peak reversal of transistor in push-pull circuit and mobile power supply

Technical Field

The invention belongs to the technical field of power supplies, and particularly relates to a method for reducing starting-up peak reversal of a transistor in a push-pull circuit and a mobile power supply.

Background

The outdoor mobile power supply is internally provided with an energy storage battery and an inversion module, and the inversion module is used for converting low-voltage direct current output by the battery into high-voltage alternating current consistent with commercial power and supplying power to a power load. In outdoor mobile power supplies, the push-pull type inversion module is widely applied due to the advantages of simple structure, high utilization rate of a magnetic core of a transformer and the like.

As shown in fig. 1, the push-pull inverter module mainly includes a push-pull circuit, a rectifying circuit, a bus capacitor, and the like. When the motor is started, the duty ratio of a driving signal of a transistor in the push-pull circuit is suddenly changed from zero to a set value, when the motor is started, the voltage at two ends of the bus capacitor is zero, and due to the characteristic that the voltage at two ends of the electrolytic capacitor cannot be suddenly changed, the bus capacitor is equivalent to a short circuit, so that the transistor has a large inverse peak.

Disclosure of Invention

In order to reduce the startup inverse peak of a transistor in a push-pull circuit, the invention provides a method for reducing the startup inverse peak of the transistor in the push-pull circuit and a mobile power supply.

Specifically, the technical scheme of the invention is as follows:

a method for reducing the turn-on peak-off of a transistor in a push-pull circuit, which is executed by a processing unit for controlling the switch of the transistor in the push-pull circuit, comprises the following steps: step S1, when the electronic device is turned on, the duty ratio of the transistor driving signal is gradually increased to a set duty ratio, where the set duty ratio is the duty ratio of the driving signal when the push-pull circuit normally works.

Preferably, before step S1, the method further includes: and step S0, acquiring the time T from starting to the bus voltage reaching the set value when the transistor of the push-pull circuit is directly controlled by the set duty ratio.

Preferably, step S1 includes: step S11, dividing the time T into a plurality of time segments; step S12 is to increase the duty ratio of the transistor driving signal step by step in a time period and to increase the duty ratio of the transistor driving signal to a set duty ratio in the last time period.

Preferably, step S11 includes: and dividing the time T into N time periods with equal duration, wherein the duration of each time period is T/N.

Preferably, the duty ratio increase amount of the first several periods is smaller than the duty ratio increase amount of the latter several periods.

Preferably, the bus voltage is sampled by a sampling resistor.

Preferably, the processing unit is a DSP chip.

A mobile power supply comprises a processing unit, a push-pull circuit, a rectifying circuit and a bus capacitor, wherein the processing unit is used for executing the method for reducing the starting-up peak-to-peak of the transistor in the push-pull circuit.

Preferably, the transistor in the push-pull circuit is a MOS transistor.

The invention has the beneficial effects that:

the processing unit is used for controlling the duty ratio of the transistor driving signal to be gradually increased, so that the bus voltage is gradually increased to a set voltage, namely a buffer process is given to the bus capacitor, and the phenomenon that the transistor peak-reversal exceeds the standard due to the fact that a larger current is generated due to the characteristics of the electrolytic capacitor at the moment of starting up the machine is avoided.

Drawings

Fig. 1 is a circuit diagram of a push-pull inverter module;

FIG. 2 is a flow chart of a method for reducing the turn-on anti-peak of a transistor in a push-pull circuit;

fig. 3 is a graph comparing the variation curves of the bus voltage.

Detailed Description

The invention is described in further detail below with reference to the figures and the embodiments.

The first embodiment is as follows:

The switching of the transistor in the push-pull circuit is controlled by the processing unit (DSP chip in this embodiment), so the duty ratio of the transistor driving signal can be controlled by the processing unit. By gradually increasing the duty cycle of the transistor drive signal without once increasing the duty cycle of the transistor drive signal to a maximum (i.e., a set duty cycle), the rate of rise of the bus voltage can be controlled, thereby preventing the transistor from having a large peak-to-peak ratio.

In this embodiment, before step S1, the method further includes: and step S0, acquiring the time T from starting to the bus voltage reaching the set value when the transistor of the push-pull circuit is directly controlled by the set duty ratio. Step S1 is: and increasing the duty ratio of the transistor driving signal from the start of starting, and increasing the duty ratio of the transistor driving signal to the set duty ratio after the time T. Increasing the duty cycle according to the time T can prevent the poor control effect on the bus voltage caused by increasing the duty cycle too much earlier than the time T, and simultaneously prevent the slow start-up caused by increasing the duty cycle too much later than the time T. In other embodiments, the time T may not be measured, and the duty cycle may not be increased according to the time T.

The bus voltage needs to be sampled when the time T is obtained, and in this embodiment, the bus voltage is obtained by sampling through a sampling resistor.

In the present embodiment, to simplify the control, step S1 includes: step S11, dividing the time T into a plurality of time segments; step S12 is to increase the duty ratio of the transistor driving signal step by step in a time period and to increase the duty ratio of the transistor driving signal to a set duty ratio in the last time period. In other embodiments, a smooth duty cycle/time function may be provided, increasing the duty cycle as a function of the curve.

In the present embodiment, to simplify the control, step S11 includes: and dividing the original required time T into N time periods with equal duration, wherein the duration of each time period is T/N. In other embodiments, the time T may be divided into a plurality of time periods of unequal duration.

In the embodiment, the duty ratio increment of the first time periods is smaller than that of the second time periods, so that the bus voltage is prevented from rising too fast. Taking the flowchart shown in fig. 2 as an example, under the condition that the set duty ratio is 46%, the duty ratio can be increased to 5% in the time period from 0 to T/6, 10% in the time period from T/6 to T/3, 20% in the time period from T/3 to T/2, 30% in the time period from T/2 to 2T/3, 40% in the time period from 2T/3 to 5T/6, and 46% in the time period from 5T/6 to T. The duty ratio may be increased at the start of the time period or at the end of the time period. Fig. 3 is a comparison graph of a bus voltage variation curve, wherein a dotted line is a variation curve of the bus voltage when the transistor is controlled by directly adopting a set duty ratio, and a solid line is a variation curve of the bus voltage when the duty ratio of the transistor driving signal is gradually increased.

Example two:

a mobile power supply comprises a processing unit, a push-pull circuit, a rectifying circuit and a bus capacitor, wherein the processing unit is used for executing the method for reducing the starting-up peak reversal of the transistor in the push-pull circuit in the first embodiment. The push-pull circuit comprises a transistor and a transformer, the control output end of the processing unit is connected with the control input end of the push-pull circuit and used for controlling the switching of the transistor, the output end of the push-pull circuit is connected with the rectifying circuit, and the bus capacitor is connected to the output side of the rectifying circuit in parallel.

In this embodiment, the transistors in the push-pull circuit are MOS transistors. In other embodiments, other types of transistors are possible.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention. It should be understood that any modification, equivalent replacement, improvement, etc. made by those skilled in the art after reading the specification, which are within the spirit and principle of the present invention, should be included in the protection scope of the present invention.

Claims

1. A method for reducing the starting-up peak reversal of a transistor in a push-pull circuit is characterized in that: performed by a processing unit controlling transistor switches in a push-pull circuit, comprising: step S1, when the electronic device is turned on, the duty ratio of the transistor driving signal is gradually increased to a set duty ratio, where the set duty ratio is the duty ratio of the driving signal when the push-pull circuit normally works.

2. The method of claim 1, wherein the method further comprises: before step S1, the method further includes: and step S0, acquiring the time T from starting to the bus voltage reaching the set value when the transistor of the push-pull circuit is directly controlled by the set duty ratio.

3. The method of claim 2, wherein the method further comprises: step S1 includes: step S11, dividing the time T into a plurality of time segments; step S12 is to increase the duty ratio of the transistor driving signal step by step in a time period and to increase the duty ratio of the transistor driving signal to a set duty ratio in the last time period.

4. The method of claim 3, wherein the method further comprises: step S11 includes: and dividing the time T into N time periods with equal duration, wherein the duration of each time period is T/N.

5. The method of claim 4, wherein the method further comprises: the duty ratio increase amount of the first several periods is smaller than that of the latter several periods.

6. The method of claim 2, wherein the method further comprises: and sampling through a sampling resistor to obtain the bus voltage.

7. The method of claim 1, wherein the method further comprises: the processing unit is a DSP chip.

8. The utility model provides a mobile power supply, includes processing unit, push-pull circuit, rectifier circuit and bus capacitor, its characterized in that: the processing unit is configured to perform the method for reducing the turn-on anti-peak of the transistor in the push-pull circuit according to any one of claims 1 to 7.

9. The mobile power supply of claim 8, wherein: and the transistor in the push-pull circuit is an MOS transistor.