Schmitt trigger-based control strategy for the discharge phase of an ultra-high-voltage bidirectional flyback

The control strategy to discharge a capacitive load such as a dielectric elastomer actuator charged to several kilo-volts is critical to obtain a safe and reliable actuation. In the case of this publication, an ultra-high voltage bidirectional flyback converter is used to not only charge a capacitive load up to 8 kV but also to discharge it back down to 0 V. To do so, a strategy based on a Schmitt-trigger circuit was implemented to limit the duration during which the current originating from the load can flow through the coupled inductor of the flyback converter to avoid the saturation of the core. Thanks to this new strategy, much shorter conduction times can be achieved compared to previously obtained results and thus much higher voltages can be manipulated.