Mitsubishi Denki Kabushiki Kaisha

Shirou Iwatani

Hirofumi Watanabe

Keiichi Komurasaki

Tatsuki Kouwa

Yoshihito Asao

Katsumi Adachi

Mitsuharu Morishita

Katsunori Tanaka

Shinichi Kouge

Katsuhiko Kusumoto

Katsuhiro Sasaki

Kyoji Matsumura

Tuneji Goda

Hirohumi Watanabe

The present invention provides an electrical power supply system for an automotive vehicle with high reliability and small size in which an adequate power is supplied to both a high power load like a blower motor and a conventional load like a battery by using a conventional alternator. The power supply system for the automotive vehicle comprises: an alternator with an armature winding and a field coil, a stepping-up DC/DC converter for applying a stepped up voltage of a battery to the field coil, a regulator for controlling an output voltage of the alternator by changing the output voltage in response to a rotating speed for supplying a power to the high power load, and for controlling the output voltage to be a charging voltage of the battery.

Vehicle electrical power supply system for supplying power to a high power load

An apparatus for controlling an output from an AC generator for a vehicle is provided which enables wiring from an external control unit to a voltage regulator by using only one wiring line, and which is capable of adjusting an output voltage of the AC generator to a usual value in accordance with a duty ratio of a control signal supplied from the external control unit, and linearly controlling the generator output voltage to a desired value in relation to a change in the level of the control signal. The apparatus includes a control unit connected to a battery and a variety of sensors mounted on a vehicle for generating a control signal which has a duty ratio corresponding to a sensed operating condition of the vehicle; and a voltage regulator connected to the battery and the control unit for detecting an output voltage of the battery and controlling turning on and off of a field current supplied from the battery to a field coil of the AC generator in accordance with the detected battery voltage so as to adjust an output voltage of the AC generator to a level that is determined in accordance with the duty ratio of the control signal from the external control unit.

Apparatus for controlling output of vehicular AC generator

An output power control device for an automotive AC generator includes a field current limiter circuit 9 for controlling the duty factor of the power transistor 305 coupled in series with the field coil 102A of the AC generator 1A, which is supplied with a maximum field current twice the conventional level. A frequency-to-voltage converter 903 converts the input frequency to a voltage corresponding to the rpm of the AC generator 1A, and a comparator 909 compares the sawtooth waveform generated by a sawtooth waveform generator 908 with the output of the frequency-to-voltage converter 903, the upper level of which is limited under a predetermined level by resistors 904 through 906 and a diode 907. When the rpm of the AC generator 1A exceeds a predetermined frequency, the pulse train generated by the comparator 909 reduces the duty factor of the power transistor 305, thereby controlling the level of the output current generated by the AC generator 1A.

Output power control device for automotive AC generator

A voltage regulator circuit 3A for a vehicular AC generator 1 includes, in addition to the conventional voltage detector and transistors, a bypass PNP transistor 315 for supplying base current to the power transistor 305 upon disconnection of the line A from the battery 4. When the engine is started and the AC generator i is driven, a small voltage is induced in the armature coil 101 due to the residual magnetism in the core of the field coil 102 even when the line A is disconnected from the battery 4. A smoothed voltage developed at the junction point between a resistor 312 and a capacitor 313 coupled serially between a phase of the armature coil 101 and ground turns on the NPN transistor 311, thereby grounding the base of the PNP transistor 315 through a resistor 314. The PNP transistor 316 is thus turned on, and the base current of the power transistor 305 is supplied through the PNP transistor 315 via the bypass line B.

Voltage regulator device for vehicular AC generator

A voltage regulator 3 for controlling the output voltage of the AC generator 1 includes two voltage dividers having junction points J1 and J2 coupled to the zener diode 306 controlling the ON/OFF of the controlling transistor 309 and the power transistor 310. The voltage level at the junction point J1 is varied by means of the short-circuiting transistor 313 in response to the output of control transistor 401. Usually, the voltage at the junction point J1 is higher than the voltage at the junction point J2, and the output voltage of the AC generator 1 is controlled on the basis of the voltage at the junction point J1 to a normal and a reduced level in accordance with the output at the target voltage change-over terminal B. When quick charging is needed, however, the control transistor 402 is turned on to ground the junction point J1, such that the output voltage of the AC generator 1 is controlled to a higher level on the basis of the voltage at the junction point J2.

Control device for a vehicular ac generator

An over current of an output transistor circuit of a voltage regulation of a vehicle mounted charging generator due to a short-circuit of a field winding thereof is detected and a capacitor is charged when the detected current is larger than a predetermined value. The voltage of the capacitor is compared with a reference voltage and the output transistor circuit is cut off during the voltage of the capacitor is larger than the reference voltage, whereby a breakdown of the output transistor circuit is prevented.

Growing community of inventors

Himeji, Japan

Shirou Iwatani