CONTROL METHOD OF ELECTRIC POWER CONVERTER

摘要

PURPOSE:To ensure an operation with a duration of conduction longer and shorter than the 1/2 cycle, by installing the function which detects the instantaneous value of the main current flowing through the semiconductor switching element and then compares it with the reference value plus the function that detects the integral value and then compares it with the reference value. CONSTITUTION:The main current flowing through the semiconductor switching element is detected by the DC converter 1 and then applied to the serial circuit of the resistor 4 and the variable resistor 5 via the diode 3 as well as to the capacitor 7 which cleared by the resetting switch 9 with every cycle via the resistor 6. The voltage of the resistor 5 is compared with the reference voltage through the comparator 10, and at the same time the integral voltage of the integrating capacitor 7 is compared with the reference voltage through the comparator 12. The comparator 10 produces the output signal when the pulse duration is <=1/2 cycle for the driving signal which is applied to the semiconductor switching element; and the comparator 12 produces the output signal when the pulse duration is >=1/2 cycle, respectively. This output signal is applied to the overcurrent protecting circuit to secure an overcurrent operation.