Denso Corporation

Tomoyuki Muraho

Tsuneo Maebara

Kazunori Watanabe

Junichi Fukuta

Akito Itou

Junichi Nagata

Tomotaka Suzuki

Yoshiyuki Hamanaka

Yoshinori Hayashi

Takeyasu Komatsu

Yohei Kondo

Syun Miyauchi

In an overcurrent determining apparatus, a temperature obtainer obtains a temperature parameter indicative of a temperature of a switching element as a temperature measurement value. A determination voltage has a first voltage value when the temperature measurement value is a first temperature. A setter sets the determination voltage to a second voltage value upon determining that the temperature measurement value is a second temperature higher than the first temperature. The second voltage value is lower than the first voltage value and higher than a value of a Miller voltage of the switching element at the second temperature.

Overcurrent determining apparatus and drive unit using the same

In a drive circuit, a rate adjuster adjusts a charging speed of a MOSFET to be faster than the charging speed of an IGBT when a drive state changer changes the first switching element from the off state to the on state first, and changes the second switching element from the off state to the on state next. The rate adjuster also adjusts a discharging speed of the MOSFET to be faster than the discharging speed of the IGBT when the drive state changer changes the MOSFET from the on state to the off state first, and changes the IGBT from the on state to the off state next.

Driving circuit for switching element and power conversion system

A drive unit includes a charging unit which charges an opening/closing control terminal of a switching element to switch a drive state. The switching element includes a sensing terminal which outputs a minute current having a correlation with current flowing between input and output terminals of the switching element. The sensing terminal and either of the output terminal or a member having a potential equal to that of the output terminal are connected via a sensing resistor. The drive unit further includes an active gate control unit which changes a charge rate based on comparison of sensing voltage, which is a potential difference across the sensing resistor, or a rate of change of the sensing voltage with a specified value. The specified value is set based on individual-difference information of the switching element which indicates a characteristic, which affects the sensing voltage, when the drive state is switched.

Drive unit for switching element

A motor control apparatus has a plurality of DC-to-AC inverter circuits which supply respective electric motors, each inverter circuit formed of a plurality of switching circuits, all of the switching circuits being connected in parallel with a smoothing capacitor which smoothes a DC voltage. A charge which remains in the smoothing capacitor, after the source of the DC voltage has become disconnected, is discharged through a single switching circuit in each of the inverter circuits, with all other switching circuits of each inverter circuit being held in a non-conducting state, thereby preventing a flow of discharge current through any of the motors.

Motor control apparatus which discharges stored charge of DC voltage smoothing capacitor when operation becomes halted

A drive circuit supplies a charging current via a charging path to drive the control terminal of a voltage-controlled switching device, with a resistor and a switching device being connected in series in the charging path. A control circuit in an integrated circuit of the drive circuit operates an internal switching device such as to selectively enable/interrupt the charging current and to regulate the voltage drop across the resistor to a fixed value. The switching device connected in the charging path can be readily changed from the internal switching device to an external switching device, in accordance with the operating requirements of the driven switching device.

Growing community of inventors

Nagoya, Japan

Tomoyuki Muraho