Abstract: An active flyback converter according to one or more embodiments may include a transformer, a first series circuit including the primary winding and a main switch connected in series at both terminals of the DC power supply, a second series circuit including a switch and a capacitor connected in series at both terminals of the primary winding, a controller that turns on and off the main switch and the switch, a rectifier smoothing circuit, and an output voltage detector that detects the output voltage of the rectifier smoothing circuit. In one or more embodiments, the controller may control a first off period from a first drive signal is turned off to a second drive signal is turns on, and a second off period from the second drive signal is turned off to a third drive signal is turned on.

Abstract: An active clamp fly-back converter is disclosed that includes a main switch electrically connected to one end of the DC power supply, a primary winding electrically connected in series with the main switch, a clamp switch electrically connected in series with the main switch, a clamp capacitor electrically connected in series with the clamp switch, a controller that controls the main switch and the clamp switch. The controller turns on and off a clamp switch two times by two pulses during off-period of the main switch.

Abstract: A detector compares a drain voltage with a first threshold voltage and outputs a first detection signal. An ON counter detects a period of time during which a current flows in a switching, counts the period of time based on a predetermined clock cycle. An OFF counter detects a period of time during which a current flow through the body diode in a state where no current flows in the switching circuit, counts the period of time. An off-time setting circuit sets the time to turn off the switching circuit. A first comparison circuit compares the cycle count value with turn off time. A second comparison circuit compares a cycle count value output by the ON counter with a comparison result output by the first comparison circuit and outputs a signal to stop transmitting a PWM signal.

Abstract: A DC-DC converter according to one or more embodiments is disclosed that may include: a drive voltage switching circuit of a drive circuit that drives a synchronous rectification MOS transistor. The drive voltage switching circuit may switch a connection so that the drive circuit supplies power from the output voltage to the drive circuit in response to the drive voltage for supplying power to the drive circuit being set to be lower than the output voltage. The drive voltage switching circuit may switch a connection so that the drive circuit supplies power from the drive voltage in response to the drive voltage for supplying power to the drive circuit being set to be higher than the output voltage.

Abstract: A detector compares a drain voltage with a first threshold voltage and outputs a first detection signal. An ON-counter detects a period of time during which current flows in a switching circuit based on the first detection signal, counts the period of time based on a predetermined clock cycle, and outputs an ON-count value. A first comparator receives the ON-count value and an ON-threshold value and outputs a first comparison signal when the ON-count value and the ON-threshold value match. A second comparator receives the ON-count value and a decreased ON threshold value, compares the ON-count value and the decreased ON-threshold value, and outputs a second comparison signal. An ON-mask time adjuster receives the second comparison signal and outputs an ON-threshold value for adjusting a mask time and a decreased ON-threshold value that is less than the ON threshold value.

Abstract: A first coupling capacitor is electrically connected in series with an input side reactor. A positive rectifier diode is electrically connected in series with the first coupling capacitor. A positive output side reactor is electrically connected to a connecting point of the first coupling capacitor and the positive rectifier diode and a ground potential. A first smoothing capacitor is electrically connected to the positive rectifier diode and a ground potential. A second coupling capacitor is electrically connected in series with the first coupling capacitor. A negative rectifier diode is electrically connected to the positive output side reactor and the second coupling capacitor. A negative output side reactor is electrically connected to a connecting point of the second coupling capacitor and the negative rectifier diode. A second smoothing capacitor is electrically connected to the negative rectifier diode, the ground potential, and the negative output side reactor.

Abstract: An excitation current detection circuit is disclosed. A transformer comprises a primary winding, an auxiliary winding, and a secondary winding. A first voltage detector detects a positive voltage of an auxiliary winding voltage. A second voltage detector detects a negative voltage of the auxiliary winding voltage. A first voltage controlled oscillator generates a first clock with a frequency proportional to the positive voltage during a period when the auxiliary winding voltage is the positive voltage. A second voltage controlled oscillator generates a second clock with a frequency proportional to the negative voltage during a period when the auxiliary winding voltage is the negative voltage. A counter outputs a counter value, which is added in one of cycles of the first clock and the second clock and subtracted in the other cycle of the first clock and the second clock as a detected value of an excitation current.

Abstract: An active clamp flyback converter includes a main switch, a primary winding that is electrically connected in series with the main switch, a clamp switch that is electrically connected to a connection point between the main switch and the primary winding, a clamp capacitor that is connected in series with the clamp switch, and a controller that outputs a first ON signal to control the main switch and a second ON signal to control the clamp switch during a period when the main switch is off. The controller outputs the second ON signal during a half cycle or more of a resonance period, in which the resonance current flowing in a resonance circuit comprising the clamp capacitor and a leakage inductance generated when the clam switch is turned on is limited by an excitation current of an excitation inductance of the primary winding.

Abstract: A detector compares a drain voltage with a first threshold voltage and outputs a first detection signal. An ON-counter detects a period of time during which current flows in a switching circuit based on the first detection signal, counts the period of time based on a predetermined clock cycle, and outputs an ON-count value. A first comparator receives the ON-count value and an ON-threshold value and outputs a first comparison signal when the ON-count value and the ON-threshold value match. A second comparator receives the ON-count value and a decreased ON threshold value, compares the ON-count value and the decreased ON-threshold value, and outputs a second comparison signal. An ON-mask time adjuster receives the second comparison signal and outputs an ON-threshold value for adjusting a mask time and a decreased ON-threshold value that is less than the ON threshold value.

Abstract: A detector compares a drain voltage with a first threshold voltage and outputs a first detection signal. An ON counter detects a period of time during which a current flows in a switching, counts the period of time based on a predetermined clock cycle. An OFF counter detects a period of time during which a current flow through the body diode in a state where no current flows in the switching circuit, counts the period of time. An off-time setting circuit sets the time to turn off the switching circuit. A first comparison circuit compares the cycle count value with turn off time. A second comparison circuit compares a cycle count value output by the ON counter with a comparison result output by the first comparison circuit and outputs a signal to stop transmitting a PWM signal.

Abstract: A DC-DC converter according to one or more embodiments is disclosed that may include: a drive voltage switching circuit of a drive circuit that drives a synchronous rectification MOS transistor. The drive voltage switching circuit may switch a connection so that the drive circuit supplies power from the output voltage to the drive circuit in response to the drive voltage for supplying power to the drive circuit being set to be lower than the output voltage. The drive voltage switching circuit may switch a connection so that the drive circuit supplies power from the drive voltage in response to the drive voltage for supplying power to the drive circuit being set to be higher than the output voltage.

Abstract: A fuel cell system includes a controller configured to execute refreshing control for removing an oxide film on a catalyst during an operation of a fuel cell, and an impedance measurer configured to measure an impedance of the fuel cell during the operation of the fuel cell. The impedance measurer executes a calculation process for calculating the impedance by using measurement values of a current and a voltage of the fuel cell in a predetermined measurement time, and outputs a substitute value prepared in advance as the impedance when the start of the refreshing control during the measurement time is detected.

Abstract: A non-contact power supply apparatus is disclosed. A power supply DC converter receives electric power and outputs a direct current. An inverter electrically connected to the power supply DC converter generates an alternating current. A coil electrically connected to the inverter allows the alternating current to flow therethrough. The power supply DC converter autonomously controls output power to decrease an output voltage when the direct current increases.

Abstract: Under a condition that a command to stop a fuel cell system is received and a state of charge of a secondary battery is equal to or lower than a threshold which is a value obtained by adding a first predetermined value to a lower limit at which electric power required to stop and start the fuel cell system is supplied, forced charging of the secondary battery by a fuel cell is performed until the state of charge reaches the threshold. After the forced charging is performed, in a case where the command to stop the fuel cell system is received within a predetermined period, the controller sets the threshold to a value obtained by adding a second predetermined value lower than the first predetermined value to the lower limit under the condition.

Abstract: When electric power requested from a load exceeds a predetermined reference value, an operating state of the fuel cell system is controlled so as to enable a normal operation mode where the fuel cell generates electric power corresponding to the requested electric power. When the requested electric power is the reference value or less, the operating state is controlled to enable an intermittent operation mode. A refresh process for sweeping current from the fuel cell and lowering the voltage of the fuel cell to a reduction voltage is executed during a shift from the intermittent operation mode to the normal operation mode. The current swept from the fuel cell at the start of the refresh process is reduced more as an oxygen amount in the fuel cell at the end of the intermittent operation mode is smaller.

Abstract: A fuel cell system to be mounted on a vehicle includes: a fuel cell for generating electric power by using reactant gas; a secondary battery capable of charging and discharging electric power; a converter electrically connected between a drive motor for driving the vehicle and the secondary battery to perform voltage conversion between the drive motor and the secondary battery; and a controller for controlling the fuel cell system.

Abstract: A fuel cell system including: a fuel cell; a voltage sensor that measures output voltage of the fuel cell; a converter that boosts the output voltage; and a control unit that controls the converter using a duty ratio including a feedforward term and a feedback term, the feedforward term being set to perform feedforward control, the feedback term being set to perform feedback control, wherein when the control unit causes the converter to boost the output voltage, and when the feedforward term calculated by specified Expression I exceeds an upper limit calculated by specified Expression II, the control unit causes the converter to boost the voltage output from the fuel cell with the duty ratio including the upper limit and the feedback term.

Abstract: A fuel cell system includes: a fuel cell stack; a voltage sensor configured to detect voltage of the fuel cell stack; a fuel cell relay connected to the fuel cell stack; a switch connected between the fuel cell stack and the fuel cell relay; an overcurrent detector configured to detect an overcurrent flowing to the switch; and a power generation stop device configured to stop power generation of the fuel cell stack when the overcurrent detector detects the overcurrent and the detected voltage becomes a specified value or less.

Abstract: Provided is a voltage control device of a fuel-cell vehicle capable of securing good acceleration responsiveness while suppressing battery deterioration even when a vehicle acceleration request is made in the situation where the output from a battery is restricted. When determining that electric power suppliable from a secondary battery to an air compressor is less than a lower limit of an acceleration maintaining-electric power of the air compressor, a voltage control device of a fuel-cell vehicle maintains a state where electric power generated by a fuel cell is consumed by an electric power drive, and supplies the electric power consumed by the electric power drive to the air compressor when a vehicle acceleration request is made.

Abstract: A fuel cell system for a vehicle includes: a fuel cell; a plurality of loads that consumes power generated by the fuel cell and includes a vehicle driving motor; a secondary battery configured to be charged with excess power when an amount of power generated by the fuel cell is greater than an amount of power consumed by the loads and to discharge shortage power when the amount of power generated by the fuel cell is less than the amount of power consumed by the loads; and a control unit configured to control the amount of power generated by the fuel cell such that an amount of charging-discharging power of the secondary battery is maintained at a predetermined value.