Abstract: A drive control apparatus is configured to drive and control a composite resonance circuit including LC resonant circuits including inductances L of power transmitting and receiving coils electromagnetically coupled to each other. The drive control apparatus includes: an inverter circuit configured to drive the composite resonance circuit by converting input DC power into AC power by switching the DC power at a predetermined operating frequency; an input current detector configured to detect an input current of the inverter circuit; and a frequency controller and driver configured to generate a drive signal of the inverter circuit while changing the operating frequency by using a predetermined extreme value search method to drive the inverter circuit, search for a resonance frequency of the composite resonance circuit based on the detected input current, and set the operating frequency based on the searched resonance frequency.

Abstract: Provided is a resonance-type power conversion circuit and the like greatly reducing computation cost with a simple configuration. The resonance-type power conversion circuit according to the present invention comprises: a resonance circuit which includes a first LC resonance circuit and a switching element and which outputs an output voltage or an output current to a load; a detection circuit which detects output information being the output voltage or the output current: a computation control unit which searches, on the basis of the detected output information, for a local maximum point in a characteristic of the output information with respect to an operating frequency and which determines the operating frequency corresponding to the searched local maximum point; and a signal generation unit which generates a drive control signal having the determined operating frequency and which applies frequency control to the switching element on the basis of the drive control signal.

Abstract: In a power converter apparatus including a PFC circuit operating in a current-critical mode, a zero point of an inductor current is accurately detected. The control circuit includes a current detector unit including a first detection circuit that detects an inductor current, amplifies a voltage corresponding to the detected current with a gain, and outputs it as a detection voltage and a comparison circuit that compares the detected voltage with a predetermined reference voltage and outputs a comparison result signal. The control circuit calculates the reference voltage for making a delay when detecting the zero value of the inductor current substantially zero, based on the detected input voltage, the detected output voltage, the preset delay time, the inductance value of the inductor, the conversion factor in current/voltage converting, the power supply voltage, and the gain, and then, outputs it to the comparison circuit.

Abstract: In an insulated resonance circuit device, a first resonance circuit includes first and second LC resonance circuits electromagnetically coupled to each other and electrically insulated from each other, oscillates at a predetermined first resonance frequency based on an input AC voltage, and outputs an oscillation signal voltage. The second resonance circuit having a second resonance frequency substantially identical to the first resonance frequency resonates with the oscillation signal voltage to detect the oscillation signal voltage, and outputs the detected oscillation signal voltage. A control circuit compare the oscillation signal voltage from the second resonance circuit with a comparison signal voltage for obtaining a predetermined target output voltage and/or a predetermined target output current to generate and output gate signals for controlling a rectifier circuit.

Abstract: At a first node (N1), an intermediate voltage potential occurs between a voltage potential of the first input terminal (P1) and a voltage potential of the second input terminal (P2). A second node (N2) is connected to ends (b1 to b3) of primary windings (w1, w4, w7) of transformers (T1 to T3) of LLC resonant converters (11 to 13). A switch circuit is connected between the first node (N1) and the second node (N2). A control circuit (15) is configured to turn on a switch circuit (SW) when a load current of a load apparatus (6) connected to a first output terminal (P3) and a second output terminal (P4) is equal to or smaller than a predetermined criterion and turn off the switch circuit (SW) when the load current of the load apparatus (6) is larger than the predetermined criterion.

Abstract: A detection circuit detects at least one of a value of a current flowing through a power transmitting coil, and a value of a current or voltage generated by an auxiliary coil. A control circuit determines a transmitting frequency based on the value detected by the detection circuit, the transmitting frequency at least locally minimizing load dependence. The control circuit determines a voltage for the transmitting power at which an output voltage of a power receiver apparatus is equal to a predetermined target voltage when generating the transmitting power having the transmitting frequency determined, and controls the power supply circuit to generate the transmitting power having the transmitting frequency and voltage determined.

Abstract: A first detector detects a value of a current or voltage generated by an auxiliary coil. A second detector detects a value of a current flowing through a power transmitting coil. A coupling coefficient estimator estimates a first coupling coefficient between the power transmitting coil and a power receiving coil, based on the value of the current or voltage generated by the auxiliary coil, and estimates a second coupling coefficient between the power transmitting coil and the power receiving coil, based on the value of the current flowing through the power transmitting coil. A control circuit controls a power supply circuit to stop power transmission to a power receiver apparatus when a difference between the coupling coefficients is greater than a threshold.

Abstract: A control circuit controls a power supply circuit to generate transmitting power having a frequency varying within a frequency range. The control circuit determines a stably transmitting frequency based on a detected output voltage of a power receiver apparatus, the stably transmitting frequency indicating a frequency of the transmitting power at which dependency of the output voltage on a load value of the power receiver apparatus is at least locally minimized within the frequency range. The control circuit determines a transmitting voltage based on the detected output voltage, the transmitting voltage indicating a voltage of the transmitting power at which the output voltage reaches a target voltage when generating transmitting power having the stably transmitting frequency. The control circuit controls the power supply circuit to generate transmitting power having the stably transmitting frequency and the transmitting voltage.

Abstract: In a power converter apparatus including a PFC circuit operating in a current-critical mode, a zero point of an inductor current is accurately detected. The control circuit includes a current detector unit including a first detection circuit that detects an inductor current, amplifies a voltage corresponding to the detected current with a gain, and outputs it as a detection voltage and a comparison circuit that compares the detected voltage with a predetermined reference voltage and outputs a comparison result signal. The control circuit calculates the reference voltage for making a delay when detecting the zero value of the inductor current substantially zero, based on the detected input voltage, the detected output voltage, the preset delay time, the inductance value of the inductor, the conversion factor in current/voltage converting, the power supply voltage, and the gain, and then, outputs it to the comparison circuit.

Abstract: A resonance oscillator circuit is provided to include first and second oscillators. The first oscillator includes a first LC resonator circuit and an amplifier element, and oscillates by shifting a phase of an output voltage with a predetermined phase difference and feeding the output voltage back to the amplifier element. The second oscillator oscillates by generating a gate signal, which has a frequency identical to that of the output voltage, and drives the amplifier element, by shifting the phase of the output voltage with the phase difference and feeding the gate signal back to an input terminal of the amplifier element, by using the amplifier element as a switching element and using the first oscillator as a feedback circuit. The phase difference is a value substantially independent of an inductance of the first LC resonator circuit and a load, to which the output voltage is applied.

Abstract: A first detector detects a value of a current or voltage generated by an auxiliary coil. A second detector detects a value of a current flowing through a power transmitting coil. A coupling coefficient estimator estimates a first coupling coefficient between the power transmitting coil and a power receiving coil, based on the value of the current or voltage generated by the auxiliary coil, and estimates a second coupling coefficient between the power transmitting coil and the power receiving coil, based on the value of the current flowing through the power transmitting coil. A control circuit controls a power supply circuit to stop power transmission to a power receiver apparatus when a difference between the coupling coefficients is greater than a threshold.

Abstract: A detection circuit detects at least one of a value of a current flowing through a power transmitting coil, and a value of a current or voltage generated by an auxiliary coil. A control circuit determines a transmitting frequency based on the value detected by the detection circuit, the transmitting frequency at least locally minimizing load dependence. The control circuit determines a voltage for the transmitting power at which an output voltage of a power receiver apparatus is equal to a predetermined target voltage when generating the transmitting power having the transmitting frequency determined, and controls the power supply circuit to generate the transmitting power having the transmitting frequency and voltage determined.

Abstract: A resonance oscillator circuit is provided to include first and second oscillators. The first oscillator includes a first LC resonator circuit and an amplifier element, and oscillates by shifting a phase of an output voltage with a predetermined phase difference and feeding the output voltage back to the amplifier element. The second oscillator oscillates by generating a gate signal, which has a frequency identical to that of the output voltage, and drives the amplifier element, by shifting the phase of the output voltage with the phase difference and feeding the gate signal back to an input terminal of the amplifier element, by using the amplifier element as a switching element and using the first oscillator as a feedback circuit. The phase difference is a value substantially independent of an inductance of the first LC resonator circuit and a load, to which the output voltage is applied.

Abstract: Provided is a transformer (1), which includes: a core (10) which forms a magnetic circuit and has a middle leg (10a) and a plurality of side legs (10b, 10c) branched from the middle leg (10a); primary windings (11) respectively wound around a first winding leg (10a) and a second winding leg (10b), which are selected from the middle leg (10a) and the side legs (10b, 10c); and a secondary winding (12) wound around either of the first winding leg (10a) or the second winding leg (10b), wherein a first magnetic flux generated by the primary windings (11) from the first winding leg (10a) and a second magnetic flux generated by the primary windings (11) from the second winding leg (10b) differ from each other by a predetermined value or more at a position at which the fluxes do not intersect with the secondary winding (12).

Abstract: The LLC resonant converter includes a bridge circuit configured to receive a DC input voltage, an LLC resonant circuit connected to the bridge circuit, a transformer connected to the LLC resonant circuit, a rectifier circuit connected to the transformer and configured to send out a converted DC voltage, a resonant capacitor changeover circuit, a bridge circuit control section, and a resonant capacitor changeover control section. When the input voltage exceeds a changeover voltage, the operating frequency is raised higher than the resonance frequency, and thereafter the switch is turned off.

Abstract: The LLC resonant converter includes a bridge circuit configured to receive a DC input voltage, an LLC resonant circuit connected to the bridge circuit, a transformer connected to the LLC resonant circuit, a rectifier circuit connected to the transformer and configured to send out a converted DC voltage, a resonant capacitor changeover circuit, a bridge circuit control section, and a resonant capacitor changeover control section. When the input voltage exceeds a changeover voltage, the operating frequency is raised higher than the resonance frequency, and thereafter the switch is turned off.

Abstract: Provided is a power converter which is applied to a power converter equipped with a switching element provided on a line, and a radiator connected to a predetermined potential such as a ground potential. A noise eliminator in which a conductive member is covered with insulator is provided between the switching element (semiconductor switch) and the radiator (heatsink). A conductive member of the noise eliminator is connected to a stable potential.

Abstract: Provided is a power converter which is applied to a power converter equipped with a switching element provided on a line, and a radiator connected to a predetermined potential such as a ground potential. A noise eliminator in which a conductive member is covered with insulator is provided between the switching element (semiconductor switch) and the radiator (heatsink). A flexible connecting line connected to a conductive member of the noise eliminator is connected to an on-board line disposed on a circuit board.

Abstract: Provided is an LLC resonant converter capable of achieving high efficiency while preventing saturation of a transformer. The LLC resonant converter includes semiconductor switches connected in series between a positive electrode and a negative electrode of a power source, a transformer including a primary winding, a core, and a secondary winding, a capacitor connected between the negative electrode of the power source and a second end of the primary winding of the transformer, a capacitor, and semiconductor switches connected to each other in series and in parallel with the capacitor, and a secondary side circuit connected to the secondary winding of the transformer, wherein the transformer is a swing choke coil.

Abstract: Provided is a transformer (1), which includes: a core (10) which forms a magnetic circuit and has a middle leg (10a) and a plurality of side legs (10b, 10c) branched from the middle leg (10a); primary windings (11) respectively wound around a first winding leg (10a) and a second winding leg (10b), which are selected from the middle leg (10a) and the side legs (10b, 10c); and a secondary winding (12) wound around either of the first winding leg (10a) or the second winding leg (10b), wherein a first magnetic flux generated by the primary windings (11) from the first winding leg (10a) and a second magnetic flux generated by the primary windings (11) from the second winding leg (10b) differ from each other by a predetermined value or more at a position at which the fluxes do not intersect with the secondary winding (12).