Abstract: A step-up transformer, an oscillator, and an ignition plug are comprised. The step-up transformer has a primary winding, a secondary winding, and a core. The ignition plug is connected to a first end of the secondary winding. A gap is formed in the core. The step up transformed is provided with a shielding part which is made of a conductive material and shields the magnetic flux leaking from the gap. A second end of the secondary winding is electrically connected to the shielding part.

Abstract: A step-up transformer, an oscillator, and an ignition plug are comprised. The step-up transformer has a primary winding, a secondary winding, and a core. The ignition plug is connected to a first end of the secondary winding. A gap is formed in the core. The step up transformed is provided with a shielding part which is made of a conductive material and shields the magnetic flux leaking from the gap. A second end of the secondary winding is electrically connected to the shielding part.

Abstract: In a high frequency plasma generation system, a magnetic resonance section is provided as a frequency multiplier section between a discharge circuit and a power booster circuit. The magnetic resonance section extracts from a fundamental wave of a predetermined frequency generated by a frequency generator higher harmonic components, which are multiplied waves of the predetermined frequency and as high as two or more integer times of the fundamental wave. A resonance frequency of the power booster circuit and a first resonance coil is set to be equal to the frequency of the multiplied wave and match to equal a resonance frequency of the discharge circuit and a second resonance coil of the magnetic resonance section when a discharge electrode and a ground electrode are in a predetermined pressure range.

Abstract: In a high frequency plasma generation system, a magnetic resonance section is provided as a frequency multiplier section between a discharge circuit and a power booster circuit. The magnetic resonance section extracts from a fundamental wave of a predetermined frequency generated by a frequency generator higher harmonic components, which are multiplied waves of the predetermined frequency and as high as two or more integer times of the fundamental wave. A resonance frequency of the power booster circuit and a first resonance coil is set to be equal to the frequency of the multiplied wave and match to equal a resonance frequency of the discharge circuit and a second resonance coil of the magnetic resonance section when a discharge electrode and a ground electrode are in a predetermined pressure range.

Abstract: A surge voltage target setting unit obtains a main circuit power supply voltage of a semiconductor power conversion device based on an inter-terminal voltage of a semiconductor switching element detected by a voltage detection unit, and sets a control target of a surge voltage in accordance with the obtained main circuit power supply voltage. An active gate control unit, when the semiconductor switching element is turned off, sets a quantity of voltage modification so as to modify a gate voltage in a direction raising the gate voltage, that is, in a direction lowering a turn-off speed, based on feedback of the inter-terminal voltage, when the inter-terminal voltage exceeds the control target.

Abstract: A surge voltage target setting unit (103) obtains a main circuit power supply voltage (VH) of a semiconductor power conversion device based on an inter-terminal voltage (Vce) of a semiconductor switching element (100) detected by a voltage detection unit (102), and sets a control target (Vm) of a surge voltage in accordance with the obtained main circuit power supply voltage. An active gate control unit (71), when the semiconductor switching element (100) is turned off, sets a quantity of voltage modification (V1) so as to modify a gate voltage (Vg) in a direction raising the gate voltage (Vg), that is, in a direction lowering a turn-off speed, based on feedback of the inter-terminal voltage (Vce), when the inter-terminal voltage (Vce) exceeds the control target (Vm).