| 摘要 |
Disclosed is a control method for a series resonant converter is provided, which includes: a feedback signal is acquired by collecting an analog output signal of a series resonant converter, and an operating frequency of the series resonant converter is changed according to the feedback signal; the series resonant converter adopts a hybrid control mode combing frequency and width modulation with width-fixed frequency modulation when lightly loaded or unloaded and a frequency modulation control mode when heavily loaded, wherein a switching can be conducted between the hybrid control mode and the frequency modulation control mode through hysteresis control. By adopting a hybrid control mode when a series resonant converter is lightly loaded or unloaded and switching between the hybrid control mode and a frequency modulation control mode through hysteresis control, the disclosure effectively addresses the problem that the voltage of a series resonant converter is unstable when the series resonant converter is lightly loaded or unloaded at a low voltage, effectively expands the output range of the series resonant converter, and also addresses the problems that it is difficult to control a loop due to the monotony of the gain of an output voltage during a duty cycle adjustment process. |
| 主权项 |
1. A control method for a series resonant converter, comprising: acquiring a feedback signal by collecting an analog output signal of the series resonant converter, and changing an operating frequency of the series resonant converter according to the feedback signal; and selecting a control mode of the series resonant converter according to a load condition, wherein the series resonant converter adopts a hybrid control mode combining frequency and width modulation with width-fixed frequency modulation when lightly loaded or unloaded and a frequency modulation control mode when heavily loaded, wherein a switching can be conducted between the hybrid control mode and the frequency modulation control mode through hysteresis control,
wherein the method further comprises: setting a frequency modulation state flag bit, presetting a switching frequency corresponding to the frequency modulation state flag bit, comparing a calculated operating frequency with a preset switching frequency, and determining the control mode of the series resonant converter according to a result of the comparison, wherein the frequency modulation state flag bit is 0 or 1, when the frequency modulation state flag bit is 0, the preset switching frequency is a first switching frequency, if the operating frequency of the series resonant converter is greater than the first switching frequency, the series resonant converter adopts the hybrid control mode, otherwise, the frequency modulation state flag bit is set to 1 so that the series resonant converter enters the frequency modulation control mode; when the frequency modulation state flag bit is 1, the preset switching frequency is a second switching frequency, if the operating frequency of the series resonant converter is smaller than the second switching frequency, the series resonant converter adopts the frequency modulation control mode, otherwise, the frequency modulation state flag bit is set to 0 so that the series resonant converter enters the hybrid control mode. |
