A.C. Generator for vehicles

An engine-driven alternating current generator for a motor vehicle comprising:

• an armature coil wound around an iron core of said generator for generating an alternating current generated voltage, said armature coil having an output terminal;
• a battery for supplying power to an electrical system of said motor vehicle, said battery having a high potential terminal and a low potential terminal;
• a power converter having at least one of high side semiconductor power elements and low side semiconductor power elements, said high side semiconductor power elements connecting said output terminal of said armature coil to said high potential terminal of said battery, said low side semiconductor power elements connecting said output terminal of said armature coil to said low potential terminal of said battery, said power converter converting said alternating current generated voltage into a direct current voltage for supplying to said battery;
• a field coil for generating a magnetic flux to said armature coil;
• and
• an exciting current controller having a switching transistor for controlling an exciting current to said field coil;
• at least one of said high side and low side semiconductor power elements in said power converter and said switching transistor in said exciting current controller including a MOS transistor structure;
• said MOS transistor structure including a withstand voltage layer;
• and
• a material of said MOS transistor structure being a compound of Si and C (SIC) such that said withstand voltage layer has a resistivity smaller than that of a MOS transistor structure which is formed of only Si, while ensuring a same withstand voltage.