| 摘要 |
PURPOSE: A current sensor of an induction cooker is provided to perform regular cooking with proper output by sensing the presence and kind of loads from the amount of electric current having rectified waveform and to protect a switching element by sensing an excess current promptly. CONSTITUTION: Line noise of AC input power is filtered through a filter(10) when the AC input power is fed from a power input terminal(1). The line noise-eliminated AC power is rectified into DC voltage through a bridge rectifier(25), and ripple elements of the DC voltage are filtered through a condenser(C4). The filtered DC voltage is charged to the condenser and to a current sensor(30). When a user turns on an operating switch(70), a control unit outputs an inverter driving signal for driving switching elements(IGBT1,IGBT2) depending on a coil electric current detected by the current sensor. The switching elements are turned on/off alternately when the inverter driving signal is fed to the base terminal of the switching element through each resistance(R1,R2) from the control unit. The second switching element(IGBT2) is turned on when the other switching element(IGBT1) is turned off at zero current. Then, the first switching element is turned on when the second switching element is turned on. An AC current of 20-30KHz flows to an induction coil(60) by alternate turning on/off of the switching elements. Thereby, an eddy current is generated over the surface of a cooking vessel(65) on the induction coil to heat the cooking vessel.
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