Abstract: A motor driving device and an air conditioner having the same of the present disclosure limits the switching of a winding switching device when there is a possibility that the winding switching device is deteriorated, in order to increase the life of winding switching device of a motor and prevent malfunction.

Abstract: A transport refrigeration unit (TRU) system is provided. The TRU system includes a TRU and an energy storage device (ESD). The TRU includes components (32) configured to control an environment in a compartment interior and a TRU controller (31) configured to control the components (32) in accordance with initial control settings and to monitor energy usage by the components (32) being controlled in accordance with the initial control settings. The ESD (40) includes an ESD controller (42) receptive of data reflective of the monitored energy usage by the components (32) from the TRU controller (31) and configured to determine whether the energy usage is above a threshold. In an event the energy usage is above the threshold, the ESD controller (42) is further configured to identify operational changes for one or more of the components (32) to reduce the energy usage and override the initial control settings of the one or more of the components (32) with new control settings.

Abstract: The heat source controller transmits the drive permission signal (SE) to the utilization controller when the compression element is drivable. The utilization controller opens a utilization expansion valve when heat exchange in a utilization heat exchanger is required, on condition that the utilization controller receive the drive permission signal (SE).

Abstract: Embodiments of systems and methods for detecting short circuits in a load are described. In an illustrative, non-limiting embodiment, a short circuit detection system includes a first circuit, a second circuit, and a controller. The first circuit has an output and an input coupled to a load and an auxiliary power source through a resistor, while the second circuit is configured to enable an output of the short circuit detection circuit for a specified period of time following application of auxiliary power at the auxiliary power source. The controller includes computer-executable instructions to monitor the output of the first circuit, and allow or disallow a main power source from powering the load based upon whether a short circuit condition exists.

Abstract: A system for measuring an angular position of a rotor with respect to a stator, wherein the rotor is rotatable around a rotation axis, the system comprising: a magnetic source mounted on the rotor, having at least four magnet poles and providing a periodically repetitive magnetic field pattern with respect to the rotation axis; a sensor mounted on the stator and comprising a plurality of sensor elements for measuring at least one magnetic field component of the magnetic field and for providing a measurement signal thereof; the sensor being located substantially centered around the rotation axis, in a plane substantially perpendicular to the rotation axis at a first distance from the magnetic source; the sensor elements being located substantially on a circle at a second distance from the rotation axis; a calculator that determines the angular position by calculating it from the measurement signals.

Abstract: A refrigeration device equipped with: a cascade cycle; a storage unit having a storage space for an object to be cooled by a second evaporator; an internal temperature sensor that detects the temperature of the storage space; a control unit that determines a second rotational speed of a second compressor on the basis of a target temperature for the storage space and the detection result from the internal temperature sensor, and that determines a first rotational speed for a first compressor having a prescribed correspondence relationship with the second rotational speed; and a first power supply unit and a second power supply unit that supply power respectively to the first compressor and the second compressor on the basis of the first rotational speed and the second rotational speed determined by the control unit.

Abstract: The present invention includes a refrigeration cycle circuit that includes compressor, indoor heat exchanger, expansion valve, and outdoor heat exchanger that are connected to each other. A working fluid containing R1123 (1,1,2-trifluoroethylene) and R32 (difluoromethane) is used as a refrigerant sealed in the refrigeration cycle circuit, and an electric motor driving device that drives an electric motor of compressor includes a rotational speed estimator. The rotational speed estimator estimates rotational speed based on information on a detection value of an electric current input to the electric motor or a magnetic pole position of a rotor that constitutes the electric motor.

Abstract: An indoor fan, an indoor heat exchanger, and refrigerant piping are housed in a casing having an air inlet and air outlets. An air conditioning indoor unit includes a first temperature sensor that measures a temperature of air in an air conditioning target space, a second temperature sensor that measures a temperature of the refrigerant piping, and a determining component that determines if there is refrigerant leakage while operation is stopped. The determining component performs a refrigerant leakage determination that is a determination whether there is refrigerant leakage based on a difference between the temperatures detected by the first temperature sensor and the second temperature sensor.

Abstract: A light bulb or fixture design is presented which provides adjustability of color temperature, adjustability of brightness, and multiple location remote control in a scalable way that is thus ideal for retrofit installations, not requiring any rewiring, installation, or setup, other than insertion of light bulbs. Rather than using any Wifi, hand held remotes, or other RF communication links, operation is controlled using only the switch or switches that are part of the existing wiring. Operation is intuitive. It allows for unified dimming and/or color temperature control of extremely large numbers of bulbs of the invention without regard for heat dissipation limitations at the physical locations of control.

Abstract: A pump and a method of operating the pump at a duty-cycle based on the input voltage of the power source energizing the pump. The pump includes at least a first opto-coupler electrically coupled to the power source. The method includes detecting at least a first opto-coupler state transition; determining a zero-crossing of the input voltage; determining an elapsed time between the zero-crossing and the first opto-coupler state transition; and operating the pump by energizing a power switch at a duty-cycle based on the elapsed time.

Abstract: An apparatus and method for controlling a linear compressor are provided. The apparatus and method may identify a kind of motor of a linear compressor, based on an output which may be measured by applying a test signal to the linear compressor, and may control the linear compressor depending on the identified kind of motor. The apparatus and method may diagnose whether the linear compressor has broken down, and thus, the kind of motor may be autonomously identified without a separate device or a measurement operation, control suitable for a characteristic or characteristics of the motor may be accurately and efficiently controlled, and maintenance, repair, and inspection of the linear compressor may be simply and easily performed.

Abstract: A method of maintaining a power supply voltage during a brownout is disclosed. The method includes the step of storing a charge in a charge reservoir (608) and storing a charge on a power supply capacitor (832). A charge from the charge reservoir is applied to the power supply capacitor in response to a power supply fail signal (BROWNOUT).

Abstract: In the coupling of bi-directional, non-freewheeling-type DC motors (24,25) to the pulling spool (23) of a canopy (11) deployment strap (21,22) and to a take-up roller (15), ratchet gears (26,27) assure automatic alignment and synchronization of the deployment and retraction mechanisms. The reverse direction rotation of the unwinding motor can be uninhibited through the slipping of its ratchet gear when the winding motor is slow to take up the pulling strap or the tarp (11) being wound thereon. The slipping provides sufficient slack to accommodate changes of spool and roller diameters as more material is successively wound thereon. A friction brake acting against a flange of die spool keeps it from spinning freely when not engaged by the motor. Winding motors can be protected against excessive power use by measuring the level of drawn current with a digital ammeter. If the current exceeds a threshold level of operation, a timer is started.

Abstract: A method of operating an inverter including the steps of detecting the temperature of the at least one electrolytic capacitor; selecting at least one of a plurality of switching patterns based on the temperature of the at least one electrolytic capacitor; and generating a ripple current across the at least one electrolytic capacitor by operating the inverter from the at least one of the plurality of switching patterns for preheating of the at least one electrolytic capacitor.

Abstract: Diagnostic and/or control methods, systems and apparatuses for variable frequency drives are disclosed. The variable frequency drive may be controlled by a controller that may conduct one or more tests or evaluations. The tests or evaluations may include determining whether a switching device in the variable frequency drive is open-circuited, short-circuited, or operating normally. The tests may include determining whether current provided at an inverter output of the variable frequency drive is within a predetermined range. An exemplary embodiment evaluates the drive for a short circuit condition, an open circuit condition, and a sensor error or failure condition, controls operation of the drive based upon these one or more evaluations, may abort operation of the drive based upon one or more evaluations, and may set a fault code indicative of the type of error encountered.

Abstract: A refrigeration cycle apparatus includes a controller configured to control opening and closing of a solenoid valve and that of a solenoid valve depending on any of a time when a compressor is activated, a time when the compressor is in normal operation, a time when a temperature of a motor of the compressor rises in the normal operation, and a time when the compressor stopped due to low-pressure cutoff is activated.

Abstract: The invention relates to a predictive maintenance method for a cooled detection module, comprising: a detector (1) comprising a matrix consisting of pixels that are sensitive to light signals; a cryostat (2) containing the detector (1); and a cooling machine (3), said method being characterized in that it comprises a step according to which a processing board (4) of the module, which is electrically connected to the detector (1), to the cryostat (2), and to the cooling machine (3) measures, stores, and processes at least: one motor current, i.e. a supply current of the machine (3); one motor voltage, i.e. a supply voltage of the machine (3); and a number of defective pixels of the detector (1). The invention further relates to a module for implementing the invention.

Abstract: A control apparatus controlling a motor for driving an object includes: a relay allowing and interrupting electric power supply to the motor; switching devices in multiple phases for allowing and interrupting energization to windings; a controller for the relay and the switching devices; a current detecting circuit for a current flowing through a merging point of the windings and the switching devices; a current limit circuit for keeping an average of the current within a predetermined range; a standard position learning device for learning a standard position of the motor; a voltage detecting circuit for detecting a voltage applied to each switching device; and an error detecting device for detecting an error in the current detecting circuit based on the voltage and the current when the relay turns on, and all switching devices turn off.

Abstract: A diagnostic monitoring system and method is employed for one or more vapor compression systems such as air conditioners and heat pumps having a compressor, an indoor air handler fan coil and an outdoor condensor. Temperature, voltage and current sensors are provided at the outdoor condensor to determine that at least one vapor compression system is operating properly. Data obtained from the sensors is wirelessly transmitted to a receiving-device for use by the systems' custodian or repair service provider and includes information concerning an occurrence of periods when one or more of the vapor compression systems are operating at an abnormal state.

Abstract: A control apparatus controlling a motor for driving an object includes: switching devices in multiple phases, each of which allows and interrupts energization to a corresponding winding of the motor; a controller for the switching devices; a current detecting circuit for a current flowing through each winding and each switching device; a current limit circuit limiting the current to match to a current limiting value; a standard position learning device learning a standard position of the motor such that the current limit circuit limits the current, and the motor rotates until the object stops at a limit position of a movable range; a rotation angle change amount detecting device detecting a change amount of a rotation angle of the object; and an error determination device determining that the current detecting circuit malfunctions when the change amount is out of a predetermined range, and the object changes between first and second states.

Abstract: A motor control device includes: a current detection portion provided to an inverter and detecting a current flowing to a motor due to a voltage generated across a current detection resistor, a timing measurement portion measuring a conduction pattern switching timing by the inverter and a current detection timing by the current detection portion, and a correction portion finding a correction current value using a current value detected by the current detection portion and the conduction pattern switching timing and the current detection timing measured by the timing measurement portion. The motor control device configured as above can enhance detection accuracy of a motor current.

Abstract: An overcurrent protection circuit and a server using the same are provided. The overcurrent protection circuit coupled between a power supply module and a load on a mainboard including a detecting component, a detection unit, a comparing unit, and a power switch. The detecting component is coupled between the power supply module and the detection unit. The detection unit detects a detecting voltage generated by the detecting component responsive to a supplying current. The comparing unit generates a control voltage according to the detecting voltage and a reference voltage. The power switch is coupled between the detecting component and the load and is controlled by the control voltage. When the comparing unit determines that the detecting voltage is greater than the reference voltage, the comparing unit cuts off the power switch to disconnect a power supply path between the power supply module and the load.

Abstract: In an installation controlling the operation of one or more motors driving a mechanism for deploying or retracting a protective canopy over the cargo compartment of a truck or wagon, a method and device for protecting the motor windings against excessive power use by measuring the level of drawn current with a digital ammeter. If the current exceeds a threshold level of operation, a timer is started. As soon as a given absolute safe period of operation is surpassed, a breaker switch is tripped interrupting the motor power supply. A plural number of trip points can be programmed into the device.

Abstract: Techniques disclosed herein include systems and methods for assembly of electric motor starter connecting packages that enable increased automation and reduced assembly via top-down assembly of circuit components, thereby allowing robotic placement, connection, and securing of circuit components. The connecting package can include an electric motor starter, with optional overload protector, packaged as one unit. The motor starter can include an electrical circuit containing a triac, current transformer, Positive Temperature Coefficient (PTC) element, resistor, and a capacitor. A cover and base of the connecting package enclose and firmly secure connected circuit elements without needing a circuit board or filler material. The device design enables quick testing of the motor starter circuit and circuit elements after being enclosed by the housing.

Abstract: When an abnormality occurs in a refrigeration cycle, the inverter motor provided in the air conditioner is stopped reliably and contacts of the main relay are prevented from degradation and fusion. A power circuit 1 of the air conditioner includes a rectifier circuit RC, a capacitor C (smoothing unit), a main relay 10 provided on a current path between the rectifier circuit RC and the capacitor C, an inverter circuit 30, a microcomputer 100, and a delay circuit 40. The microcomputer 100 has an inverter circuit control unit 110, a main relay opening/closing control unit 120, a waveform forced cut-off unit 130, and a cut-off signal output unit 140.

Abstract: A power supply control device includes an inverter having plural switching elements, an inverter controller that controls the inverter, a device power supply that generates a first power supplied to the inverter controller, a detector that detects whether there is an abnormality relating to the compressor, and a power supply controller. The inverter generates drive voltages usable to drive a compressor motor that is a drive source of a compressor as a result of the switching elements switching on or off, and outputs the drive voltages to the compressor motor. The power supply controller stops generation of the first power by the device power supply to thereby stop the control of the inverter controller in a case where there is an abnormality relating to the compressor.

Abstract: An electric vacuum pump actuating module for boosting the braking force of a motor vehicle, including a main controller and a driver circuit for operating the electric vacuum pump. The driver circuit includes a first and a second switch. The first switch switches a supply voltage above a predefined voltage level of an operating voltage of the vacuum pump. The second switch switches a supply voltage below the voltage level of the vacuum pump. The main controller controls the first switch by first control signals and the second switch by second control signals. The actuating module determines a state of the electric vacuum pump as a first piece of information based on a first response of the electric vacuum pump resulting from the first or second control signals. The actuating module assesses the state of the electric vacuum pump as error-free or erroneous operation of the electric vacuum pump.

Abstract: A unit for recording operating information of an electronically commutated motor (ECM) is described. The unit includes a system controller communicatively coupled to an ECM. The system controller includes a processing device configured to control the unit. The unit also includes a memory device communicatively coupled to the system controller. The memory device is configured to receive and store ECM operating information provided by the processing device.

Abstract: It is judged whether the abnormal current is due to the electric leakage or not by a detection step detecting the abnormal current by the leakage current detection board and comparing a threshold value of predetermined items stored in a storing unit and actual values corresponding to the items at the time of when a compressor is stopped by detecting the abnormal current in the detection step. Specifically, the abnormal current is recognized as the electric leakage to be displayed on a display unit when at least one of the operating time at the time of detecting the abnormal current, the inner pressure of a motor, and a discharge pipe temperature is lower than the corresponding threshold value.

Abstract: A system for protecting a three-phase electric motor of a compressor, the motor receiving first, second, and third phases from a three-phase power supply, the system including a single-phase line break protector, a first current sensor, and a control module. The single-phase line break protector disconnects the motor from the first phase in response to a temperature being greater than a predetermined temperature threshold. The first current sensor measures a current through the single-phase line break protector. The control module determines a current value based on the measured current, and disconnects the motor from the second and third phases in response to the current value being less than or equal to a predetermined threshold.

Abstract: Techniques disclosed herein include systems and methods for assembly of electric motor starter connecting packages that enable increased automation and reduced assembly via top-down assembly of circuit components, thereby allowing robotic placement, connection, and securing of circuit components. The connecting package can include an electric motor starter, with optional overload protector, packaged as one unit. The motor starter can include an electrical circuit containing a triac, current transformer, Positive Temperature Coefficient (PTC) element, resistor, and a capacitor. A cover and base of the connecting package enclose and firmly secure connected circuit elements without needing a circuit board or filler material. The device design enables quick testing of the motor starter circuit and circuit elements after being enclosed by the housing.

Abstract: One or more attributes (e.g., pan, gain, etc.) associated with one or more objects (e.g., an instrument) of a stereo or multi-channel audio signal can be modified to provide remix capability. An audio decoding apparatus obtains an audio signal having a set of objects and side information. The apparatus obtains a set of mix parameters from a user input and an attenuation factor from the set of mix parameters. The apparatus then generates a plural-channel audio signal using at least one of the side information, the attenuation factor or the set of mix parameters.

Abstract: The present disclosure includes a compressor for use with an air-conditioner. The compressor includes a motor having a stator and a rotor. A compressing portion intakes gas, compresses gas and discharges gas. The compressor includes a protector located near the motor. The protector is connected in series to the circuit of the motor stator coil. The protector has a temperature sensitive element that trips the protector in response to the temperature sensitive element being heated to a predetermined drive temperature. A thermal resistance heater connects in parallel to the temperature sensitive element. The compressor can be includes with an air-conditioner, having an evaporator, a condenser, a throttling member and the compressor.

Abstract: A heat source apparatus in which a control device of the heat source apparatus can ascertain a stoppage of an inverter device and in which a stable operating time of the heat source apparatus can be extended is provided. The heat source apparatus includes an electric compressor that is driven by an inverter device and that compresses a refrigerant, the inverter device having a protective function that performs stoppage for device protection on the basis of a predetermined calculation by an inverter control portion, and a control device that controls cold output and/or heat output. The control device includes an inverter-protective-function estimating unit that estimates a calculation result of the protective function of the inverter control portion.

Abstract: An aircraft electrical system comprises a generator to be driven as part of a gas turbine engine. The generator supplies electrical power to a plurality of accessories associated with the gas turbine engine, and to an aircraft power bus in parallel to the supply to the accessories. A control detects a short circuit on the aircraft power bus. When a short circuit is detected on the aircraft power bus, a switch is driven open to disconnect the aircraft power bus from the generator. In this manner, the power will continue to be delivered to the plurality of accessories. In a separate feature, a control voltage is provided by an auxiliary permanent magnet generator to a voltage regulator for the main generator.

Abstract: When an abnormality occurs in a refrigeration cycle, the inverter motor provided in the air conditioner is stopped reliably and contacts of the main relay are prevented from degradation and fusion. A power circuit 1 of the air conditioner includes a rectifier circuit RC, a capacitor C (smoothing unit), a main relay 10 provided on a current path between the rectifier circuit RC and the capacitor C, an inverter circuit 30, a microcomputer 100, and a delay circuit 40. The microcomputer 100 has an inverter circuit control unit 110, a main relay opening/closing control unit 120, a waveform forced cut-off unit 130, and a cut-off signal output unit 140.

Abstract: A scroll compressor for compressing fluid has a common terminal block for electrical hook-ups. The compressor includes a compressor section; a drive unit operative to drive the compressor section for compressing fluid; a protection module; and a power connector for connecting electrical power to the drive unit to facilitate operation of the scroll compressor bodies. The common terminal block provides for connection to the protection module and the power connector for the compressor.

Abstract: A detection and alarm circuit includes a transformer, a rectifier, and an alarm. A first input terminal of the transformer is connected to a ground terminal of an electronic device, and a second terminal of the transformer is grounded. A first output terminal of the transformer is connected to a first input terminal of the rectifier, and a second output terminal of the transformer is connected to a second input terminal of the rectifier. A first output terminal of the rectifier is connected to a first terminal of the alarm. A second output terminal of the rectifier is connected to a second terminal of the alarm.

Abstract: A current detection device for detecting an electric current flowing through an inverter, an overcurrent level generation device for generating an abnormality judgment reference value, an overcurrent detection device for generating an interruption signal to the inverter on the basis of an output of the current detection device and the abnormality judgment reference value, and an adjusting apparatus for correcting the abnormality judgment reference value of the overcurrent level generation device on the basis of the output at a time when a constant electric current is applied to the current detection device are provided. The overcurrent level generating device is provided with one or a plurality of resistance value adjusting sections, and generates the abnormality judgment reference value in correspondence to a resistance value of the resistance value adjusting section.

Abstract: A brushless direct current motor, includes a rotor which comprises a permanent magnet, a stator which comprises coils associated with a plurality of phases which form an electrical field for generating a torque by interaction with a magnetic field which is generated by the permanent magnet, and a load prevention part which is disposed inside the stator to electrically connect and disconnect the coils of the plurality of phases according to a temperature variation.

Abstract: The present invention discloses a control apparatus for a linear compressor which can vary a cooling force and prevent an inrush current. The control apparatus for the linear compressor includes a coil winding body laminated on the linear compressor, a first capacitor connected in series to the coil winding body, a capacitance varying unit being formed in a parallel structure to the first capacitor, and having a capacitor switch, and a control unit for inducing an output change of the linear compressor, by varying the whole capacitance of the control apparatus by controlling the capacitor switch.

Abstract: Adaptive intelligent circulation control methods and systems are used to help increase the comfort and/or reduce energy usage and equipment wear. In one illustrative embodiment, the circulation and/or ventilation time is adjusted based on one or more environmental conditions inside or outside the building structure. In another illustrative embodiment, the circulation and/or ventilation time may be adjusted based on the current time of day, current time of year, and/or the current schedule period. In another illustrative embodiment, the circulation and/or ventilation time is randomized over time. The start time, end time, and/or length of a circulation and/or ventilation cycle may be randomly set.

Abstract: An improved housing for a computing device is disclosed. The improved housing can have one or more of the following aspects. One aspect of the invention pertains to a computing device provided with an internal antenna. One aspect of the invention pertains to a stiffener for a computer housing so as to increase the rigidity and strength of the computer housing. One aspect of the invention pertains to a lid for a computing device, such as a portable computer, that is provided with a translucent housing.

Abstract: A motor controller (101) according to the invention comprises an inverter circuit (3) for driving a brushless motor (4) and a control unit for controlling the rotational speed of the brushless motor (4) by controlling the phase of the motor current of the brushless motor (4) through the inverter circuit (3).

Abstract: In an overload protective apparatus of a compressor and its method capable of preventing damage of a compressor due to overload by removing an overload protector and using an operation control device operating the compressor, the overload protective apparatus includes a reference current setting unit for presetting a reference current value for operating the compressor normally; a microcomputer for generating a power cutoff signal when the detected current value is greater than the reference current value and generating a power supply signal when the detected current value is smaller than the reference current value; and a power supply unit for cutting off power applied to the compressor on the basis of the power cutoff signal or applying power to the compressor on the basis of the power supply signal.

Abstract: Systems and methods are disclosed to construct subsurface images from diffuse seismic energy. Various disclosed system embodiments include multiple seismic sensors that each convert received seismic energy into one or more seismic signals. One or more processor combine the seismic signals to determine a subsurface map. As part of determining the map, the processor(s) systematically focus the array of seismic sensors on each bin in the subsurface volume of interest. In this manner each bin becomes a focal point of the array. For each bin, the processor(s) analyze the seismic wave travel time to each seismic sensor and apply a corresponding time shift to align the seismic signals with a uniform travel time. The time-shifted seismic signals are then combined to determine an intensity value for seismic energy radiating from the focal point. A subsurface map can then be derived from the intensity value as a function of position.

Abstract: An inverter-integrated electric compressor enhances vibration resistance of an inverter apparatus integrated with a housing without degrading cooling performance, reduction in weight, or the ease of assembly of the inverter apparatus. An inverter-integrated electric compressor 1 has an inverter apparatus 22 integrated with an inverter storage box 11 of a housing 3. The inverter apparatus 22 includes a metal plate 23 secured in an inverter storage box 11; a plurality of power semiconductor switching elements 24 mounted on the metal plate 23; a power substrate 25 on which a power-related control circuit for operating the power semiconductor switching elements 24 is mounted; and a busbar assembly 26 formed by integrating a plurality of busbars with an insulator. The metal plate 23 includes a protrusion 33 extending in a width direction perpendicular to a motor shaft direction L of an electric motor.

Abstract: A method for detecting compressor or system degradation or malfunction in a multiple circuit compressor system includes the steps of providing a multiple circuit compressor system including at least a first circuit and a second circuit; and comparing a first value corresponding to an operating parameter of the first circuit with a second value corresponding to an operating parameter of the second circuit.

Abstract: A diagnostic system for determining whether a rotor shaft of a compressor is unbalanced. The compressor includes a displacement sensor that measures the displacement of the rotor shaft as it is rotating. The sensor dynamic frequency signal is sent to a bandpass filter that filters out an eigen-frequency frequency that is a function of shaft elasticity and rotor dynamics. The filtered frequency signal is then rectified by a rectifier to make the filtered frequency signal positive. The rectified signal is then passed through a low pass filter that converts the rectified signal to a DC signal. The DC signal is then sent to a controller that determines if the amplitude of the signal is above a predetermined threshold, which indicates a problem with the balance of the compressor.

Abstract: In regenerative braking mode, an inverter converts, according to PWMC signal from a control unit, an AC voltage generated by a motor into a DC voltage to supply the converted DC voltage to an up-converter which down-converts the DC voltage to charge a DC power supply. The control unit receives voltage V2 from a voltage sensor to stop the up-converter if voltage V2 is higher than a predetermined value. The control unit further receives voltage Vf from a voltage sensor that is applied to a DC/DC converter and stops the up-converter if voltage Vf is higher than a predetermined value. Moreover, the control unit receives voltage V1 of the DC power supply from a voltage sensor to stop the up-converter if voltage V1 does not match voltage V2.