Control method and apparatus for series resonance DC/DC converter

A technology of DC converter and series resonance, which is applied in the field of control method and device of series resonant DC/DC converter, can solve the problems such as frequency modulation control magnetic components are difficult to optimize circuit loss, etc., and achieve good reliability and dynamic characteristics, and circuit Simple, strong engineering effect

CN100541992CInactive Publication Date: 2009-09-16EMERSON NETWORK POWER CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2009-09-16
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a method and device for controlling series resonant DC / DC converter, and the device includes a drive circuit, a series resonant circuit, a PI regulator, a discriminator, a PWM circuit and a variable-frequency control circuit. And the method: sampling a feedback signal from a load circuit, making PI conversion on the feedback signal, and determining the working state of a load according to the converted result; as the load is in a light- or no- load state, using a PWM signal at stable frequency and duty factor changing with the feedback signal as a driving pulse of the drive circuit so as to make the series resonant circuit work in a PWM control state; otherwise using a pulse signal at stable duty factor and frequency changing with the feedback signal as a driving pulse of the drive circuit so as to make the series resonant circuit work in a variable frequency state.
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Description

technical field

[0001] The invention relates to DC power conversion technology, in particular to a control method and device for a series resonant DC / DC (DC / DC) converter. Background technique

[0002] Miniaturization and high frequency are the development trend of power supply today, but the switching frequency is too high to bring about the problem of excessive loss of the switching tube, which cannot be solved by the traditional BUCK converter, but the series resonant converter can better solve it this problem.

[0003] The series resonant DC / DC converter adopts resonant conversion technology. Since the resonant element works in a sinusoidal resonant state, the voltage on the switching tube naturally crosses zero, which can realize zero-voltage turn-on, and the power loss is very small. This topology usually uses variable frequency modulation to stabilize the output voltage by changing the operating frequency. figure 1 It is the basic form of the LLC series resonant DC / ...

Examples

Embodiment Construction

[0039] The present invention combines frequency modulation control and pulse width modulation (PWM) control to control the series resonant circuit, adopts frequency conversion control when the operating frequency of the power supply is low, and introduces PWM control mode when the operating frequency of the power supply is too high, so as to prevent the load from working at The problem of excessive frequency rise and excessive circuit loss at light load or no load.

[0040] refer to Figure 2A As shown, the DC / DC converter includes a drive circuit, a series resonant circuit, a PI regulator, a discriminator, a pulse width modulation circuit and a frequency conversion control circuit. The driving circuit outputs a control signal to the series resonant circuit according to the received driving pulse, and the series resonant circuit converts the rectified input DC power supply to the load circuit under the control of the control signal.

[0041] The input end of the PI regulator ...