Peak and Valley Current Mode Control Using Double Compensation Ramp
| 754 - Abstract: |
| The invention concerns the field of electrical power supply, including AC/AC, AC/DC, DC/AC and DC/DC power switching converters. It is a closed-loop control concept, primarily relevant to current regulation but also to voltage regulation. It allows to reach the maximum bandwidth frequency, at given switching frequency. In turn power supply products can have better dynamic performances, hence lower mass and cost. ESA is looking for partners who would be interested in licensing and implementing this patent. |
Description
The present invention consists in extending average current mode control with symmetrical sawtooth beyond its limit to reach peak current mode control “with symmetrical compensation ramp”. The symmetrical compensation ramp necessary to implement such peak current mode control shall consist in two asymmetrical compensation ramps. This is the essence of the invention, as illustrated on the figure below.
By substituting the upper (in blue) and lower (in violet) compensation ramps to the symmetrical sawtooth (dotted line) relevant to symmetrical Average Current Mode control, the current waveform is allowed to move from low gain (in green) to higher, optimal, gain (in red) relevant to Peak and valley Current Mode control.
Innovations and advantages:
As yet, current mode control would resort to average control with asymmetrical sawtooth, or peak control with asymmetrical compensation ramp or average control with symmetrical sawtooth. Considering that average current control (with negligible integral loop gain) is a subset of peak current control, the missing link was peak current control with symmetrical compensation ramp. It constitutes the ultimate control strategy because peak current control has superior dynamics with respect to average current control and because symmetrical sawtooth or compensation ramp offers a factor 2 on the bandwidth performance with respect to asymmetrical sawtooth or compensation ramp. In turn, power supply products can have implemented with reduced mass and cost.
Domain of application:
The scope of applications of the invention is quite extensive as it concerns not only DC/DC power supplies for space, but also AC/DC, DC/AC and AC/AC power supplies for terrestrial (50 Hz) or aeronautical (400 Hz) applications.