128results about How to "Suppress surge voltage" patented technology

A PDP driving circuit is comprised of a power recovery unit for recovering an electric power from a capacitive load by resonance operation with PDP which is the capacitive load Cp, and reusing the recovered power. The power recovery unit includes a recovery inductor for resonating with the capacitive load, a recovery switch element for connecting the recovery capacitor to the capacitive load and recovery inductor, and forming a channel for passing resonance current, a counterflow preventive diode for blocking flow of current in the recovery switch element in reverse polarity direction, and a protective diode for forming a closed current channel including the recovery inductor and recovery switch element when the counterflow preventive diode is changed from ON state to OFF state.

The invention discloses a surge suppression circuit which comprises a voltage input end, a voltage output end, a field-effect tube, a transistor, a capacitor, a first resistor, a second resistor and a third resistor, wherein the voltage input end is connected with the source electrode of the field-effect tube and the emitting electrode of the transistor respectively; the voltage input end is also connected with the drain electrode of the field-effect tube through the first resistor; the collector electrode of the field-effect tube is grounded through the third resistor; the base electrode of the transistor is connected with the drain electrode of the field-effect tube through the second resistor; and the drain electrode of the field-effect tube is grounded through the capacitor and also connected with the voltage output end. The surge suppression circuit suppresses surge voltage effectively; after the circuit is in a steady state, the power consumption of the surge suppression circuit is reduced; the surge suppression circuit has the function of load short circuit protection; and when an external power supply generates surge voltage, the surge suppression circuit offers dynamic and real-time protection.

When it is applied to the IGBT1 with high withstand voltage, it is necessary to connect the diodes 5 with high withstand voltage in series in multiple stages, and there is a problem of high cost or reduced reliability. In addition, the collector voltage detection circuit 6 performs Short-circuit detection lags significantly, and there is a problem that sometimes the IGBT1 cannot be protected. The solution is that the sampling circuit 16 detects the gate voltage Vge during the detection processing period of the allowable gate voltage Vge, and if the gate voltage Vge exceeds the reference value, It is determined that an abnormality has occurred in the IGBT11.

Aspects of the invention are directed to a three-level power converter that has, as one phase, a bidirectional switching element connected to the series connection point of a series circuit of a first insulated gate bi-polar transistor (“IGBT”) and second IGBT and an intermediate electrode of a direct current power supply. Also included is a fuse connected between the bidirectional switching element and the intermediate electrode of the direct current power supply, and an overcurrent shutdown unit provided in each gate drive circuit of the first and second IGBTs, are provided as protection from a power supply short circuit phenomenon occurring in the event of a short circuit failure of any of the IGBTs or diodes.

The invention discloses a surge inhibiting circuit, which comprises the following parts: voltage input end, voltage output end, field effect pipe, transistor, capacitance, first resistance, second resistance, wherein the voltage input end connects the source pole of field effect pipe and launching pole of transistor, which also connects the leak pole of field effect pipe through first resistance; the integral electrode of transistor connects ground through the second resistance; the basic pole of transistor connects the integral electrode of transistor and grid and leak pole of field effect pipe; the leak of field effect pipe connects ground through capacitance; the leak pole of field effect pipe connects the voltage output end. The invention can inhibit surge voltage effectively, which reduces the power consumption of stable working effectively due to little inner resistance of transistor and also provides short-circuit load protecting function.

A device and method are provided for a charger for vehicles. In particular, the charger includes, an AC / DC converter configured to convert a commercial alternating current power source to a direct current power source and a DC / DC converter configured to convert the direct current power source applied from the AC / DC converter to a battery charging power source. The direct current power source is supplied to a battery. The DC / DC converter includes a snubber circuit that reduces the magnitude of a ripple current of the charging power source.

The present invention includes: a main voltage detection unit for detecting a voltage applied between main electrodes of an electrical power switching element; a control current source for injecting a current into a gate electrode of the electrical power switching element in accordance with the voltage detected by the main voltage detection unit; a main current detection unit for detecting a main current flowing between the main electrodes of the electrical power switching element; and an adjustment unit for adjusting a current of the control power source in accordance with the main current detected by the main current detection unit.

A method and device for controlling the electric motor. The method for controlling a motor current supplied to an electric motor by using an inverter device is provided. The inverter device includes an inverter circuit and a capacitor connected to an input of the inverter circuit. The method includes controlling the inverter circuit in such a manner as to supply an alternating electric current to the electric motor after the temperature of the capacitor reaches a temperature at which a maximum acceptable motor current value becomes greater than or equal to a value at which the torque necessary for starting the electric motor is produced.

A gate drive circuit includes a driver for driving a gate of a switching element, a peak voltage detector, and a drive capacity calculator. The peak voltage detector detects a peak voltage at a main terminal of the switching element when the switching element is OFF. The drive capacity calculator calculates a voltage difference value between the detected peak voltage and an allowable voltage value at the main terminal of the switching element, where the allowable voltage is based on the specifications of the switching element. The drive capacity calculator changes a drive capacity of the driver to gradually decrease the difference between the detected peak voltage and the allowable voltage.

A switchgear control apparatus includes a zero point interval detecting circuit, an interruption time judgment circuit and a reclosing time decision circuit. The zero point interval detecting circuit detects time intervals between successive zero points of a main circuit current. The interruption time judgment circuit judges that interruption time of the main circuit current is time of a zero point immediately preceding a zero point at which a difference between the time interval between two successive zero points and half the period of a commercial AC voltage exceeds a specific value. Upon detecting the gradient of the main circuit current at the interruption time, the reclosing time decision circuit sets reclosing time at a point in phase where the AC voltage has a maximum negative value if the gradient is positive, and at a point in phase where the AC voltage has a maximum positive value if the gradient is negative.

A device and method are provided for a charger for vehicles. In particular, the charger includes, an AC / DC converter configured to convert a commercial alternating current power source to a direct current power source and a DC / DC converter configured to convert the direct current power source applied from the AC / DC converter to a battery charging power source. The direct current power source is supplied to a battery. The DC / DC converter includes a snubber circuit that reduces the magnitude of a ripple current of the charging power source.

The present invention provides a switching power supply unit and a voltage converting method capable of suppressing a surge voltage applied to an output rectifier element more effectively. Energy in the direction of suppressing reverse voltages (surge voltages) applied to a plurality of rectifier diodes is injected into a rectifier circuit. Reverse voltages applied to the plurality of rectifier diodes are maintained to be lower than a voltage to be inherently applied for a predetermined period. Therefore, rise in the surge voltage is suppressed and rectifier elements (rectifier diodes) having low withstand voltage can be used.

The present invention provides a switching power supply unit capable of suppressing a surge voltage generated in a rectifier element more effectively. A first resonance circuit is constructed by capacitors in a surge voltage suppressing circuit and an inductor, and resonance time of the first resonance circuit is set to be longer than recovery time of a diode in a rectifier circuit. According to at least one of a DC input voltage and an output current, either a first bridge circuit or a second bridge circuit is selectively allowed to perform switching operation. At the time of forward-direction operation, the first resonance circuit is formed by the capacitors in the surge voltage circuit and the inductor on the high voltage side. At the time of reverse-direction operation, a second resonance circuit is formed by the capacitors and an inductor on the low voltage side.

The present invention relates to a drive control apparatus for an electric motor and a control method thereof. In the present invention, the generation of electric brake is suppressed while protecting a semiconductor relay from excessive surge voltage. The drive control apparatus is configured to include: a drive circuit for controlling the drive of the electric motor; a semiconductor relay arranged on a drive line between the drive circuit and the electric motor to cut off current supply from the drive circuit to the electric motor; and an active clamp circuit for turning on the semiconductor relay when a potential difference between the drive circuit side and the electric motor side of the semiconductor relay is greater than or equal to a predetermined value.

A transformer that realizes ZVS operation includes a primary winding and a secondary winding. A control circuit turns switching elements on and off in a complimentary manner in order to repeatedly invert the voltage applied to the primary winding. A conduction path supplies a voltage excited in the secondary winding to a load connected between a high-potential side and a ground side of the secondary winding. A first rectifier diode has a rectification direction extending from the high-potential side toward the ground side of the load and is provided along the conduction path. A second rectifier diode and a capacitor, which are connected in series with each other, are connected in parallel with the secondary winding. An inductor is connected in parallel with the second rectifier diode. A rectification direction of the second rectifier diode matches the direction extending from the high-potential side to the ground side.

The invention relates to a control circuit and a power supply for suppressing the surge voltage and current of a power supply, comprising a driving circuit and a power supply output terminal, whereinthe driving circuit receives the output voltage of the power supply and generates a driving signal according to the output voltage; and a voltage monitoring circuit which monitors the output voltage of the power supply and conducts and outputs a conduction signal when the power supply generates a surge voltage; a voltage and current limiting circuit respectively connected with a driving circuit and a negative output terminal of the power supply; a switch protection circuit is respectively connected with a driving circuit, a voltage monitoring circuit and a voltage and current limiting circuit;when the output voltage of the power supply is normal, the voltage and current limiting circuit conducts according to the driving signal to make the output voltage of the power supply normal; When the surge voltage is generated from the power supply, the switching protection circuit conducts according to the conduction signal output from the voltage monitoring circuit, so that the voltage and current limiting circuit limits the output voltage and output current of the power supply. This scheme can restrain the surge voltage and current of the power supply, so as to achieve the effect of protecting the power supply and the load.

A gate driver includes: a gate drive unit configured to drive a gate of a switching element in accordance with an input signal that commands to turn on or to turn off the switching element; a timing determination unit configured to measure an on-time width from when the input signal is switched to an on-command to when the input signal is switched to an off-command, and configured to determine, based on the measured on-time width, an intermediate timing that is before switch-off surge voltage of the switching element reaches a peak; and a driving condition changing unit configured to change a gate driving condition of the switching element at the intermediate timing determined by the timing determination unit.

For enhancing performance of the electrostatic discharge protection for a semiconductor IC (integrated circuit), the electrostatic discharge protection circuit includes: a power source system for supplying a current to a semiconductor IC in the semiconductor device through a power source potential line and a reference potential line; a primary protection circuit for releasing a surge current to the power source system through a first node connected to a signal terminal when the surge current is generated at the signal terminal; a trigger circuit for generating a trigger signal in response to a surge voltage generated at the power source system; and a secondary protection circuit. The secondary protection circuit releases the surge current to the power source system through a second node connected between the first node and the semiconductor IC in response to the trigger signal, so that the surge voltage can be rapidly suppressed near the semiconductor IC.

An F connector coupled to a transmission line applies a radio frequency (RF) signal to an RF input of a filter of a set-top box via an impedance matching network that includes a first inductor and a second inductor that are coupled in series. A capacitor and a third inductor are coupled in parallel between a discharge tube and a junction terminal that is interposed between the series coupled inductors for protecting electronic components such as the filter from a voltage surge developed in the transmission line.

A drive unit of a semiconductor element including: a drive circuit for driving a control electrode of a voltage control semiconductor element to which a freewheeling diode is connected in anti-parallel; a resistor connected between the control electrode and the drive circuit; a capacitor having one terminal connected between the resistor and the control electrode; and a switch element connected between another terminal of the capacitor and a low-voltage-side electrode of the voltage control semiconductor element, wherein a control electrode of the switch element is connected to a connection point of the resistor and the capacitor.

According to an embodiment of the invention, there is provided a semiconductor device comprising: a semiconductor element having a first main electrode, a second main electrode and a control electrode, a current flowing between the first and second main electrodes being controlled by a control signal which is input between the control electrode and the second main electrode; and a capacitor formed by providing an insulating layer between the second main electrode and the control electrode of the semiconductor element.

An electric wire holding member (20) includes: a main body portion (21) formed in a cylindrical shape having a central axis line (X1); a plurality of electric wire accommodating portions (22a, 22b, and 22c) provided to penetrate through the main body portion (21) along the central axis line (X1), respectively, and are formed to be capable of individually accommodating electric wires (3a, 3b, and 3c), respectively, the electric wire accommodating portions (22a, 22b, and 22c) being disposed along a circumferential direction around the central axis line (X1) at equal intervals in a cross section as viewed from an axial direction; and a space portion (23) formed between two electric wire accommodating portions adjacent to each other along the circumferential direction to penetrate through the main body portion (21) along the central axis line (X1).

There are provided: a voltage division circuit (13) that performs voltage division of the voltage applied between the main electrodes of a non-latching switching element (11) having two main electrodes and a single control electrode at voltage division elements (14a) to (14c); a control current source (16) that injects current at the control electrode in accordance with the divided voltage of main voltage detection voltage division elements, of the voltage division elements (14a) to (14c) of the voltage division circuit (13) and a voltage division ratio control circuit (20) that adjusts the voltage division ratio of the main voltage detection voltage division elements (14b), (14c) of the voltage division circuit (13) in accordance with a control signal for controlling the switching element (11).

A switching circuit (80) includes: a plurality of insulated gate transistors (30-33) connected in parallel between a high voltage line (L1) and a low voltage line (L2); gate resistors (50-53) each provided for one of the plurality of insulated gate transistors (30-33) and each including a first terminal connected to a gate electrode of each of the insulated gate transistors (30-33); and a single gate voltage application unit (60) configured to apply pulsing gate voltage to the gate electrode of each of the insulated gate transistors (30-33) via the gate resistors (50-53). A second terminal of each of the gate resistors (50-53) provided for each of the plurality of insulated gate transistors (30-33) is connected to the gate voltage application unit (60) via a gate voltage apply line (L3), and a single capacitor is connected between the gate voltage apply line (L3) and the high voltage line (L1).