Tdk Corporation

Tdk-lambda Corporation

Densei-lambda Kabushiki Kaisha

The University of Electro-communications

Nippon Electric Industry Co., Ltd.

Tdk-lameda Corporation

Kabushiki Kaisha Campuscreate

Eiji Takegami

Kazushi Nakano

Kazushi Watanabe

Satoshi Tomioka

Kouji Higuchi

Tatsuyoshi Kajikawa

Takeshi Kamono

Tomokazu Ikarashi

Jun Kawakami

A power conversion apparatus includes an input power terminal, an output power terminal, a power conversion circuit, a signal generation circuit, and a control circuit. The power conversion circuit converts supplied electric power and outputs the converted electric power. The power conversion circuit includes a sensor that generates a first detection signal corresponding to an output voltage or an output current. The signal generation circuit generates a second detection signal corresponding to the first detection signal. The control circuit controls operation of the power conversion circuit. The signal generation circuit includes a corrector, a photocoupler, and an output circuit. The corrector performs correction processing on the first detection signal. The photocoupler includes a light receiving device generating a light reception signal. The output circuit outputs the second detection signal corresponding to the light reception signal. The corrector performs the correction processing corresponding to a current transfer ratio of the photocoupler.

Power conversion system with increased detection accuracy

A power supply includes a synchronous rectification-type rectifying/smoothing circuit to increase the conversion efficiency of an output voltage, avoids cost increases, and can change the output voltage and maximum output current. The power supply includes synchronous rectifiers connected to secondary windings of a transformer, smoothing circuits that smooth a voltage outputted from the synchronous rectifiers to produce an output voltage, switch drivers that correspond to the synchronous rectifiers and operate on one or both of the output voltage outputted from the smoothing circuits connected to the synchronous rectifiers and an AC voltage generated in the secondary windings to drive synchronous rectification switches of the synchronous rectifiers, and an output connector that is disposed following the smoothing circuits and connects the outputs of the smoothing circuits in a connection pattern selected out of serial and parallel.

Power supply and medical system

A power supply includes: a power factor correction circuit that includes a capacitor and converts an input voltage, produced by rectifying an AC input voltage, to a DC, output voltage; a current detector that detects an inflow current for the power factor correction circuit and outputs a current detection signal; an output voltage detector that detects the output voltage and outputs an output voltage detection signal; a voltage difference detector that detects a voltage difference between maximum and minimum values of a pulsation component of the output voltage detected from the output voltage detection signal; a working life determiner that compares the voltage difference and a threshold and gives notification of end of life of the capacitor when the voltage difference reaches the threshold; and a threshold updater that updates the threshold in keeping with the detected inflow current detected based on the current detection signal.

A power supply can be driven in parallel in a master-slave arrangement using fewer wires. Each power supply includes: input terminals; output terminals; a master terminal; a slave terminal; a switching power supply that switches an inputted voltage and executes one of a constant-voltage operation that outputs a DC voltage of a target voltage value and a constant-current operation that outputs a DC current of a target current value; an indicative voltage generator that generates a current detection signal indicating the current outputted from the output terminals, superimposes a bias voltage (&#x3e;a threshold voltage), and outputs to the master terminal; and an operation switcher that compares a voltage applied to the slave terminal and the threshold voltage and outputs, based on the result, a control signal for switching to the constant-voltage operation or the constant-current operation, to the switching power supply.

A power supply includes: a power converter that converts an input voltage by switching at a switch and supplies an output voltage and an output current to an output terminal connected to a load; a current detector that detects the output current or a current that changes with the output current and outputs a current detection signal whose voltage value changes with the output current; a signal corrector that inputs and corrects the current detection signal and generates and outputs a corrected current detection signal whose voltage value corresponds to the value of the output current; a matching circuit that inputs the corrected current detection signal and outputs to a balanced terminal; and a controller that inputs the corrected current detection signal and a balanced voltage signal generated at the balanced terminal and controls switching operations of the switch to reduce a difference between the two signals.

Power supply

A control device and method are provided for a power supply device which can perform stable constant voltage constant current control with high responsiveness with a simple configuration. The control device includes: a voltage difference value generation unit which subtracts an output voltage value from a voltage target value to generate a voltage difference value; a current difference value generation unit which subtracts an output current value from a current target value to generate a current difference value; a difference value selection unit which compares the voltage difference value or a value based on the voltage difference value with the current difference value or a value based on the current difference value, and selects the smaller one as a control difference value; and an operation amount generation unit which generates an operation amount for controlling the power supply device based on the control difference value.

Control device and control method for power supply device

A bidirectional DC-DC converter is configured with a transformer that has a first winding and a second winding, a first DC-AC converter that is provided between a first DC voltage line and the first winding, a second DC-AC converter that is provided between a second DC voltage line and the second winding, and a controller that performs a switching control operation that bidirectionally transmits DC power between the first DC voltage line and the second DC voltage line. When the bidirectional DC-DC converter is in a light load operation state, the controller provides an operation stop period that periodically stops the switching control operation so as to perform an intermittent switching control operation.

Bidirectional DC-DC converter and method of controlling bidirectional DC-DC converter

A controller controls a voltage-source power converter and a current-source power converter based on a detection value of a rail voltage input to the voltage-source power converter and a detection value of a charging voltage output from the current-source power converter, at the time of charging operation.

DC-DC converter

A current-fed isolation converter includes a coil that is connected to a primary side of a transformer, a power source that supplies electric power to the primary side of the transformer, a switching element that controls a first electric current flowing in the coil, a snubber circuit that includes a rectifying element and a capacitive element that is charged by a second electric current flowing in the rectifying element, and a step-down power supply circuit that regenerates electric charge of the capacitive element to the power source. The snubber circuit controls an excess voltage that is generated when the switching element is turned off. The power supply circuit maintains a charging voltage of the capacitive element at a predetermined voltage value.

Current-fed isolation converter

A DC-DC converter is configured with a voltage-source power converter at a primary side of a transformer, a current-source power converter at a secondary side of the transformer, and a controller. The DC-DC converter is connected between a storage battery and an inverter that drives an electric motor. The controller generates a first control input based on a voltage between input and output terminals of the voltage-source power converter, a second control input based on a voltage between input and output terminals of the current-source power converter, and a command value for PWM or PFM control based on the first and second control inputs and an input-output current flowing between one of the input and output terminals of the voltage-source power converter and the current-source power converter. Therefore, it is easy to switch between a powering state and a regenerating state.

A DC-DC converter is configured with a voltage-source power converter provided at a primary side of a transformer, a current-source power converter provided at a secondary side of the transformer, and a controller. The controller generates a first control input based on a voltage between input and output terminals of the voltage-source power converter, a second control input based on a voltage between input and output terminals of the current-source power converter, and a command value for PWM or PFM control based on the first and second control inputs and an input-output current flowing between one of the input and output terminals of the voltage-source power converter and the current-source power converter. Therefore, it is easy to switch between a powering state and a regenerating state in the DC-DC converter.

DC-DC converter and method for controlling DC-DC converter

A DC-DC converter is configured with a voltage-source power converter at a primary side of a transformer, a current-source power converter at a secondary side of the transformer, and a controller. First and second voltage detection circuits respectively detect first and second voltages of the voltage-source and the current-source power converters. A current detection circuit detects an input-output current of the current-source power converter. The controller controls the voltage-source and the current-source power converters to transfer power between the primary side and the secondary side of the transformer. The controller includes a calculation unit that performs calculations based on the first voltage, the second voltage and the input-output current, and a table unit that include a plurality of parameter sets. The calculation unit performs the calculations based on one of the plurality of parameter sets that is selected from the table unit.

There is provided a digital controller which can reduce a variation in output voltage as compared to the conventional digital controller at the time of abrupt changes in load and in input of a power amplifier. The digital controller is built in the power amplifier for supplying an output voltage vto a load and is equipped with a manipulated variable calculating unit which detects the output voltage vto calculate a manipulated variable &#x3be;and a signal generating unit which converts the manipulated variable &#x3be;into a signal for making the power amplifier operate. A feedforward function from an equivalent disturbance qy caused by the variation in the load is replaced by a feedback function from the output voltage vand the manipulated variable &#x3be;, thereby allowing a transfer characteristic from the disturbance qy to the output voltage vto result in a quadratic differential characteristic. Consequently, the variation in output voltage can be reduced as compared to the conventional controller at the time of the abrupt changes in the load and in the input of the power amplifier.

Digital controller for controlling output voltage under large variations in load and supply voltage

There is provided a digital controller which can generate no oscillation even if sensing a load side and enables control of supplying a desired voltage to the load. In an power amplifier which supplies an output voltage vto the load connected via a load connecting line, a load voltage vand the output voltage vare periodically sampled to calculate a manipulating variable &#x3be;from the output voltage v, the load voltage vand an arbitrary target value r. Based on the manipulating variable &#x3be;calculated, a control signal is output to the power amplifier. As a result, when connecting an LC filter with a load deviceof the power amplifier intended for a control target and besides the load connecting line is long, a robust digital controller without generating oscillation even if sensing the load side is performed can be realized.

Digital controller

A robust digital controller is equipped with a high degree of approximation and is able to incorporate a novel two-degree-of-freedom robust digital control system without substantially considering the magnitude of the control inputs and there is provided its designing device. A control compensating means is configured as an integral type control system in which a discrete transfer function W(z) between a target value r and a controlled variable y is approximated to a higher-approximate quadratic approximate model transfer function W(z) and an arithmetic processing can be performed within the digital controller based on the model transfer function W(z). Further, the designing device automatically calculates parameters constituting the control system. Consequently, a robust digital controller can be easily realized that is equipped with a high degree of approximation as compared with a conventional approximate digital control system for realizing a first-order model and is robust against output noises.

Growing community of inventors

Tokyo, Japan

Eiji Takegami