Method for generating PWM signals and a pulse width modulation power converter

1. A method for generating PWM signals, comprising:

generating an output voltage according to a pulse width modulation signal and an input voltage;

generating an error signal by sampling the output voltage and differencing the sampled output voltage and an output voltage reference;

determining a duty ratio that defines a duty cycle of a pulse width modulation signal by a PID controlling algorithm;

generating the pulse width modulation signal by providing the duty ratio to a pulse width modulator; and

continuously monitoring the duty ratio within one nominal PWM period by computing and comparing a plurality of consecutive duty ratios within said one nominal PWM period, said comparing comprising computing a duty ratio difference between the consecutive duty ratios, and in case the duty ratio difference exceeds a threshold during an off-time of the pulse width modulation signal, the pulse width modulator is triggered to start a new nominal pulse width modulation period earlier than a next scheduled PWM cycle.

2. The method according to claim 1 wherein the duty ratio is monitored in case a load transient is detected.

3. The method according to claim 2 wherein the load transient is detected by continuously monitoring the error signal.

4. The method according to claim 1 , wherein the output voltage and/or the error signal is oversampled by sampling a plurality of error signals within the one nominal PWM period.

5. The method according to claim 1 , wherein a moving average of the error signal is computed.

6. The method according to claim 1 , wherein a first set of PID coefficients is selected in case a steady state is detected and a second set of PID coefficients is selected in case a load transient is detected.

7. The control method according to claim 6 , wherein a nonlinear gain KP is selected in case of load transient detection.