Driver for switching element and control system for rotary machine using the same

A control system for controlling a rotary machine, the control system comprising:

• an inverter equipped with a pair of upper- and lower-arm switching elements, connected in series, for each of plural phases, each of the upper- and lower-arm switching elements having an input terminal, an output terminal, an on-off control terminal, and a sense terminal from which a sense current correlated with a current flowing between the input and output terminals is output;
• and
• a driver for driving each of the upper- and lower-arm switching elements to thereby invert a DC voltage inputted to the inverter into an AC voltage to be supplied to the rotary machine,
• the driver for each of the upper- and lower-arm switching elements comprising:
• a charging module configured to charge the on-off control terminal of the corresponding switching element for turning on the corresponding switching element;
• so a clamping module configured to execute a clamping task that clamps a voltage at the control terminal to be equal to or lower than a predetermined voltage as a clamp voltage for predetermined time during the charge of the on-off control terminal of the corresponding switching element, the clamp voltage being lower than an upper limit of the voltage at the on-off control terminal of the corresponding switching element;
• a measuring module configured to measure a value of a parameter correlated with the sense current;
• a limiting module configured to discharge the on-off control terminal to limit flow of the current between the input and output terminals of the corresponding switching element if the value of the parameter measured by the measuring module exceeds a threshold value;
• and
• a setting module configured to variably set a length of the predetermined time as a function of the value of the parameter measured by the measuring module during the charge of the on-off control terminal of the corresponding switching element.