Adjustable fly-back or buck-boost converter

摘要

In fly-back and buck-boost converters (21, 22), to reduce distortions and to increase distortion power factors, arrangements (1) are introduced for adjusting control signals generated by controllers (2) for controlling switches (3) of the converters. The arrangements (1), in response to increased/decreased amplitudes of voltage signals from voltage supplies (4) for feeding the converters, increase/decrease durations of conducting times of the switches (3). This way, unwanted losses in the grid and power generators are avoided. The converters are relatively low cost single stage converters. Preferably, the durations are substantially proportional to sums of the amplitudes of the voltage signals and design parameters. These design parameters may comprise amplitudes of other voltage signals such as output voltages. Arrangements (1) are provided for controllers (2) that can only produce fixed durations as well as for controllers (2) that can produce adaptable durations via adaptable external elements.

主权项

1. A controller for controlling a switch of a converter, the converter configured to be coupled to a voltage supply, the controller configured to be coupled to the voltage supply and further configured to:
receive a voltage signal of the voltage supply; and generate a control signal such that a duration of conducting time of the switch of the converter is longer at a higher instantaneous amplitude of the voltage signal and that the duration of the conducting time of the switch is shorter at a lower instantaneous amplitude of the voltage signal, wherein the control signal is such that the duration of the conducting time of the switch is substantially proportional to a sum of the amplitude of the voltage signal and an amplitude of another voltage signal, wherein the controller further comprises a circuit comprising: an input terminal for receiving the voltage signal, an output terminal to be coupled to a control input of the controller, and a common terminal, a transistor coupled to the common terminal, and a serial connection of at least one capacitor coupled to the common terminal, wherein the at least one capacitor is coupled to the output terminal.