219 may charge the control power supply unit 201 by using the electric energy accumulated in the power supply unit 213 instead of the alternator connected to the engine 215 fig2 a and 2b are diagrams for describing a function of the auxiliary power supply unit 219 of fig1 as a charger referring to fig2 a and 2b the power supply unit 213 may include an engine auxiliary motor 301 an inverter 303 a dc link capacitor 305 a converter 307 and an ultra capacitor 309 the inverter 303 charges the dc link capacitor 305 by the engine auxiliary motor 301 here the engine auxiliary motor 301 may be directly connected with the engine 215 and rotate at the same revolutions per minute rpm as that of the engine during driving of the engine the converter 307 charges the ultra capacitor 309 by using electric energy stored in the dc link capacitor 305 a detailed configuration of the power supply unit 213 and a function thereof are widely known matters and thus further detailed descriptions will be omitted the auxiliary power supply unit 219 may be connected to the dc link capacitor 305 as illustrated in fig2 a or connected to the ultra capacitor 307 as illustrated in fig2 b to receive the accumulated electric energy here the ultra capacitor 307 may be substituted with the large capacity battery when the voltage of the control power supply unit 201 is stepped down to a predetermined voltage or lower the control power supply unit 201 may be charged by connecting the auxiliary power supply unit 219 with the control power supply unit 201.