| 摘要 |
PROBLEM TO BE SOLVED: To provide a heater control device in which heater disconnection can be certainly identified and judged without using a voltage system. SOLUTION: The heater control device includes a power adjustment device 13 in which a thyristor 13A is turned on in a half period zone based on a phase control angle corresponding to a temperature adjustment control signal for every half period zone of alternating current and then the thyristor is turned off at a zero cross position of the half period zone to adjust the current actual value of the alternating current, and based on the current actual value, the heater current to the heater is adjusted and output, and a heater disconnection detecting device 16 to detect the heater disconnection based on the heater current. The heater disconnection detecting device calculates the thyristor ON-duration time, period, and current actual value based on the heater current, and calculates the phase control angle based on the ON-duration time and period, and calculates the current actual value equivalent to a control amount 100% based on the current actual value and the phase control angle, thereby, the heater disconnection is identified and judged based on this current actual value. COPYRIGHT: (C)2009,JPO&INPIT
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