Abstract: If a main stop valve of a fuel gas tank is not opened, it becomes possible to display a remaining level of fuel gas. A remaining fuel level displaying method for the fuel cell system comprises: if the main stop valve is opened, then calculating a remaining level of fuel gas in the fuel gas tank using a pressure value acquired from the pressure sensor, and displaying the calculated remaining level of the fuel gas on a display device, and if the main stop valve is closed, then displaying on the display device a remaining level of the fuel gas that was stored into a memory at a time when the main stop valve was shut off.

Abstract: A driving frequency setting portion is provided. The driving frequency setting portion sets a switching frequency of a switching element on the basis of a notification from a driving phase number switching portion. A ripple current detected by a current sensor is in inverse proportion to inductance of reactor. Since a ripple current becomes the largest in the single-phase driving, in this embodiment, considering both the ripple current and switching loss, a switching frequency for the single-phase driving is set higher than a switching frequency for multiphase driving.

Abstract: A rotatable performance device, such as a yo-yo, is modifiable such that the device can act as a relatively responsive device for beginners and a relatively stable device for advanced users. Spacers that facilitate these modifications and a method for configuring the spacers to change the device's responsiveness and stability are also disclosed.

Abstract: A voltage boost converter includes: a main voltage boost portion that has a first switch and a first coil, and that raises output voltage of a direct-current power source by using counter electromotive force of the coil caused by the switch performing a switching action on the coil; and a subsidiary voltage boost portion which has a capacitor that adjusts potential difference between two poles of the switch by amount of electricity stored, and which reduces switching loss of the switch by adjusting the amount of electricity in the capacitor during the switching action, and which has a second switch and a second coil. The second coil is formed by winding a wire around at least a portion of a core formed of a magnetic body. The core is provided with a gap formed of a non-magnetic body. A core region formed of a magnetic body is adjacent to the gap.

Abstract: Provided is a converter control device which detects an on-failure of an auxiliary switch constituting an auxiliary circuit of a soft switching converter and can prevent element failures. A current sensor for detecting the current flowing in a coil is provided between a fuel cell and the. A controller sequentially detects current by use of the current sensor and makes a judgment as to whether or not the detected current has exceeded an overcurrent threshold value stored in a memory (not shown). When the controller judges that the current has exceeded the overcurrent threshold value, the controller judges that a second switching element has an on-failure, and performs a fail-safe operation by stopping the driving of a converter (for example, a U-phase converter) of an auxiliary circuit provided with this second switching element.

Abstract: A voltage conversion circuit apparatus that adjusts a timing skew between the switching control of the first switching element and the switching control of the second switching element includes: a skew storage portion that stores a timing skew between the switching controls of the first and second switching elements after the voltage conversion circuit apparatus is manufactured; and a timing adjustment portion that corrects the stored timing skew and thereby adjusts the timing relation between a first pulse signal and a second pulse signal so as to bring within a permissible range the timing skew that occurs when the switching controls of the first and second switching elements are performed by using the first pulse signal and the second pulse signal.

Abstract: A rotatable performance device, such as a yo-yo, is modifiable such that the device can act as both a relatively narrow looping yo-yo and a relatively wide string trick yo-yo. Inner lobe spacers that facilitate these modifications and a method for attaching the spacers to the rotatable performance device to change its play characteristics are also disclosed.

Abstract: A power conversion system includes a first switching DC-DC converter circuit including a first switching device, a second switching DC-DC converter circuit connected in parallel with the first switching DC-DC converter circuit and including a second switching device, and a snubber capacitor connected in parallel with each of the first switching device and the second switching device. The power conversion system is configured such that a frequency of driving the first switching DC-DC converter circuit is higher than a frequency of driving the second switching DC-DC converter circuit, and an equivalent series inductance of a closed circuit including the first switching device and the snubber capacitor is smaller than that of a closed circuit including the second switching device and the snubber capacitor.

Abstract: A fuel cell system includes a fuel cell, a multiphase voltage conversion device with N-phases (N being an integer equal to or larger than two) that is connected to the fuel cell, a control signal generation portion that generates control signals to control each phase of the multiphase voltage conversion device by superimposing a control waveform for measuring impedance on a voltage indicating an output target voltage of the multiphase voltage conversion device and sequentially outputs the control signals corresponding to N phases with a predetermined phase difference to the multiphase voltage conversion device, and an impedance calculation portion that measures a current and a voltage of the fuel cell on cycles corresponding to N predetermined sampling frequencies having a phase difference equal to the predetermined phase difference and calculates an impedance of the fuel cell based on the measured current and the measured voltage.

Abstract: The present invention detects a failure in an FC converter. A target voltage determination section determines an output target voltage for a fuel cell. A superimposition signal generation section generates a predetermined reference signal to be superimposed onto the output target voltage. A voltage command signal generation section generates a voltage command signal by superimposing the reference signal onto the output target voltage. A frequency characteristics calculation section calculates the frequency characteristics of the reference signal component superimposed on the output voltage of the fuel cell. A failure judgment section judges that a failure occurs in the FC converter if a value of the calculated frequency characteristics is less than the lower limit threshold value of an allowable range established based on reference characteristics.

Abstract: There is disclosed a converter controller which can simply and early detect an abnormality of an auxiliary circuit constituting a soft switching converter. On turning off a first switching element, a controller detects a voltage between both the ends of a snubber capacitor and a voltage between both the ends of the first switching element, to obtain a difference voltage. The controller compares the obtained difference voltage with a voltage threshold value stored in a memory (not shown) to judge whether or not the difference voltage is larger than the voltage threshold value. When the difference voltage is smaller than the voltage threshold value, the controller judges that an auxiliary circuit is normal, to end processing, whereas when the difference voltage is not less than the voltage threshold value, the controller judges that a failure (an open failure) occurs in the auxiliary circuit, to shift to a fail safe operation, thereby ending the processing.

Abstract: An apparatus comprises: a voltage monitoring unit for monitoring input direct-current voltages of first and second converters whose output ends are connected in parallel to each other; and a judgment control unit for judging that an output diode of the first converter is short-circuited, when an input direct-current voltage monitored by the voltage monitoring unit with respect to the first converter rises up to a post-step-up voltage stepped up by the second converter during a step-up operation of the second converter.

Abstract: A fuel cell system includes a fuel cell, a motor connected to the fuel cell, an FC boost converter which raises the output voltage of the fuel cell to output the voltage to the motor, an inverter, and a controller which controls the fuel cell, the FC boost converter and the inverter. When abnormality occurs in one of the FC boost converter and the inverter, an abnormality signal does not pass through a converter control unit or an inverter control unit but is transmitted to the other device, thereby enabling the stop of both the FC boost converter and the inverter.

Abstract: A fuel cell system capable of improving the voltage controllability of a converter provided in the system is provided. A controller judges whether or not a passing power of a DC/DC converter falls within a reduced response performance area for the number of active phases as of the present moment. When the controller determines that the passing power of the DC/DC converter falls within the reduced response performance area, the controller determines the number of phases which avoids the driving within the reduced response performance area, and outputs a command for switching to the determined number of phases (phase switching command) to the DC/DC converter.

Abstract: Between a direct-current power source and a connection point where a resonance current flowing in an opposite direction from a main current joins the main current from the direct-current power source in a resonant converter, there is provided a current blocking circuit which blocks the resonance current toward the direct-current power source. In consequence, it is possible to prevent the reverse charging of the direct-current power source with the resonance current which realizes soft switching in the resonant converter.

Abstract: A load variation detecting section determines whether or not the actual load variation falls below a load variation threshold stored in a memory. If a load variation detecting section determines that a specific time period (for example, one minute) has elapsed since the actual load variation fell below a load variation threshold, a power supply section applies same power to reactors for the respective phases. On the other hand, a heat dissipation property calculating section measures temperature-rise rates of the elements for the respective phases, ranks the rates in order from the one having a higher heat dissipation property, and notifies the priority drive phase determining section of the result. A priority drive phase determining section chooses a phase having the highest heat dissipation property as a priority drive phase.

Abstract: A fuel cell system capable of improving the voltage controllability of a converter provided in the system is provided. A controller judges whether or not a passing power of a DC/DC converter falls within a reduced response performance area for the number of active phases as of the present moment. When the controller determines that the passing power of the DC/DC converter falls within the reduced response performance area, the controller determines the number of phases which avoids the driving within the reduced response performance area, and outputs a command for switching to the determined number of phases (phase switching command) to the DC/DC converter.

Abstract: A heat-release configuration includes a printed board on which a semiconductor component is mounted, a heat-release plate which is mounted on the semiconductor component, and configured to diffuse heat generated by the semiconductor component; and a supporting clamp which is mounted on the heat-release plate, and configured to fix the heat-release plate to the printed board via a hole provided in the printed board, the supporting clamp including a sectional L-shape in a horizontal direction having two flat surfaces substantially orthogonal to each other, the supporting clamp having on a lower side of each of the flat surfaces a leading end portion which is inserted into the hole of the printed board and a locking claw which is formed in the leading end portion and projects outside the L-shape.

Abstract: A chopper circuit includes an input unit that inputs a main turn-on signal for turning on a main switching element and an auxiliary turn-on signal for turning on an auxiliary switching element; and a prohibiting unit that prohibits the main switching element from turning on unless the auxiliary turn-on signal is input.

Abstract: Provided is a fuel cell system that can suitably control a voltage converter in response to a judgment that an abnormal condition occurs in a power detection unit that detects a power passing through the voltage converter. The fuel cell system has: a first power detection unit that estimates an effective value of a converter input power by multiplying the converter input power, which is obtained from a battery voltage and a battery current, by a converter efficiency; a second power detection unit that estimates a converter output power from a fuel cell voltage, a fuel cell current and a driving motor load power; and a third power detection unit that estimates a converter flowing power from a current of a reactor measured by a current sensor (shown in a separate drawing). The fuel cell system also has similar detection units for current, and using one of the detection units or a combination of some of them, specifies a malfunctioning sensor and prohibits correction of parameters.