Denso Corporation

Daisuke Mizuno

Masahiro Tsuchida

A valve timing controller has the drive circuit which performs a feedback control of the energization to the electric motor based on the target rotation speed and the actual rotation speed of the electric motor, and rotates the electric motor to the target rotation direction. An invalid switch part of the drive circuit suspends the feedback control at the time of change of the target rotation direction.

Valve timing controller

A valve timing controller includes a driving circuit, a control circuit, and a signal line. Receiving electric power from a power source, the drive circuit drives an electric motor according to the control signal, and outputs the rotative direction signal showing the rotation direction of the electric motor. A controlling circuit outputs the control signal generated according to the rotation-direction signal. A signal line transmits the rotation-direction signal to the controlling circuit from the drive circuit. The drive circuit outputs a high-level signal showing the normal rotation direction, and a low level signal showing the reverse rotation direction of the electric motor. When a power supply voltage falls below to the acceptable value, the drive circuit maintains the voltage level of the signal line at high level.

A motor controller includes an inverter circuit, a speed detector, an amplifier, a voltage detector, and an offset voltage addition circuit. The inverter circuit drives a motor based on a PWM signal. The speed detector generates an actual speed signal corresponding to an actual speed of the motor. The amplifier outputs a differential voltage by amplifying a difference between the actual speed signal and a target speed signal. The voltage detector outputs a switch signal for switching rotation direction of the motor. The switch signal has a first level, when the differential voltage is equal to or greater than a predetermined value. The switch signal has a second level, when the differential voltage is less than the predetermined value. The offset voltage addition circuit adds an offset voltage to the differential voltage according to the signal level of the switch signal.

Motor controller

A valve timing controller includes a driving circuit, a control circuit, and a signal line. The driving circuit controls electricity applied to the electric motor according to a control signal, and generates a rotation-direction signal which indicates a rotation direction of the electric motor by a voltage level. The control circuit outputs the control signal which is generated according to the rotation-direction signal. The rotation-direction signal is transmitted from the driving circuit to the control circuit through the signal line. The driving circuit outputs the rotation-direction signal of high-level during a predetermined period after the control signal is outputted.

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Kariya, Japan

Daisuke Mizuno