Abstract: A control system and method for an inverter-based resource device provided in a synchronous power grid. The control system includes at least one inverter based resource device connected to an electrical power system, and a controller module. The inverter based resource device includes a reference power Pref, a combination module and a transfer function. The inverter based resource device injects modulated power into the power system. The power system (which is represented by a transfer function in the control system) receives an undesirable forced oscillation, which is connected to a measuring device. A controller module processes the measured output and provides a control signal to the inverter based resource device. The controller is arranged to suppress a forced oscillation detected in the power system.

Abstract: The present invention provides a control apparatus (100) that includes a remaining capacity change model determination unit (120) that determines a remaining capacity change model that estimates a temporal change of a remaining capacity which is based on charging/discharging in accordance with a first energy service for each of a plurality of energy storage systems that perform charging/discharging in accordance with energy services; and an operation planning unit (130) that computes a charging/discharging plan of each of the plurality of energy storage systems based on the remaining capacity change model of each of the plurality of energy storage systems.

Abstract: Disclosed is a system that reduces fault currents in a power grid, thereby reducing the risk of unintentionally igniting a fire when an object comes in proximity to a high voltage power line. The circuit comprises an isolation transformer, a neutral connection, a current compensating device, and an automatic recloser or other circuit interrupting type protection system. The isolation transformer may comprise a delta-delta or delta-zigzag transformer with a one-to-one ratio between the input and output voltages and phase angle. The current compensating device is connected to the neutral and configured to redirect a substantial portion of a fault current to ground through the isolation transformer neutral instead of the fault itself. The current compensating device may comprise an arc suppression coil tuned to match the capacitance of the three phase outputs, or an inverter.

Abstract: A method for operating a renewable energy power plant comprising a plurality of renewable energy generators, a plurality of power dissipation systems and a battery storage system is provided. The method comprises steps of: monitoring the statuses of the power dissipation systems; performing a ramped active power recovery operation following a voltage deviation, and controlling the battery storage system during the ramped active power recovery operation to absorb power generated by the renewable energy generators in dependence on the monitored statuses of the power dissipation systems.

Abstract: A voltage stability monitoring device and a method capable of obtaining information of voltage stability that can be served to practical use within a range of assumed conditions during a predetermined monitoring period are provided. The present invention provides a voltage stability monitoring device for estimating a voltage stability by using a voltage stability curve representing the voltage stability in an electric power system, including a voltage stability limit prediction unit for predicting a voltage stability limit, a voltage stability calculation condition determination unit for determining voltage stability calculation conditions by using a prediction result of voltage stability limit, a voltage stability curve calculation unit for calculating the voltage stability curve using a result of the voltage stability calculation condition determination, and a voltage stability margin calculation unit for calculating a voltage stability margin using a calculation result of the voltage stability curve.

Abstract: An auxiliary power supply device includes a parasitic diode forming a parallel circuit together with a second switching element and connected in a forward direction to a main power supply, and a parasitic diode forming a parallel circuit together with a fourth switching element and connected in a reverse direction to an auxiliary power supply. When a state parameter indicates that a reaction force that interferes with operation of an assist motor is applied, an electronic control unit turns ON a first switching element, turns OFF the second switching element, turns ON a third switching element, and turns OFF the fourth switching element. A regenerative current from the assist motor flows to the auxiliary power supply via an inverter, the third switching element, and the parasitic diode.

Abstract: A motor drive system includes at least one current sensor disposed within a housing of the motor drive system. The at least one sensor is configured to detect a current of output power produced by the motor drive system. The motor drive system also includes a controller configured to determine a resonant frequency of a cable connected to the motor drive system based at least in part on the detected current, and to adjust pulse width modulation (PWM) switching of the motor drive system based at least in part on the determined resonant frequency of the cable.

Abstract: An apparatus, system, and method for controlling functions of a vehicular alarm. The method includes receiving one or more signals including location information, determining a location of the vehicle using the location information, setting one or more functions based on the location information, determining whether an alarm function is activated, and activating the one or more functions according to the setting upon determining that an alarm has been activated. The method may further include using GPS data or signals transmitted from one or more base stations (e.g., from cellular telephone base stations, computer networks, proprietary transmitters, etc.) to determine the position of the apparatus (e.g., installed in the vehicle). The apparatus may also inform a user of regulations relating to an area dependent upon its location.

Abstract: A power conversion circuit for converting DC power supplied from a DC power supply to AC power; and a power conversion control section for controlling operation of the power conversion circuit so as to generate autonomous operation power as an AC voltage source in a parallel-off state from a power grid. The power conversion control section includes: an AC voltage control section for controlling AC voltage; an AC current suppression section for limiting AC current to a predetermined current limit value or smaller; and a DC voltage shortage suppression section for, when DC voltage of the power conversion circuit reduces, in response thereto, reducing the current limit value to be given to the AC current suppression section.

Abstract: An apparatus for reducing a magnetic unidirectional flux component in the core of a transformer, i.e., a three-phase transformer, includes a plurality of compensation windings that are magnetically coupled to the core of the transformer, wherein a controllable current source for feeding current into the compensation windings is arranged electrically in series with the compensation windings, specifically with the neutral point thereof, which is forming by the inputs of the compensation windings, and a neutral earthing transformer is electrically connected to the outputs of the compensation windings, where the current source electrically interconnects the neutral point of the compensation windings and the neutral point of the neutral earthing transformer.

Abstract: Provided is a relay unit that can sufficiently suppress defects that are caused by an insulation failure of insulating member that insulates and separates a load power supply from a device power supply, and a method for controlling a relay circuit. A control unit includes an insulating member diagnosis unit that performs diagnosis of an insulation failure of the capacitor.

Abstract: In a method for controlling the state of charge (SOC) of a battery power plant (1), which for controlling at least one physical quantity (P, f) is connected to an electric energy distribution network (2), the state of charge (SOC) of the battery power plant (1) is detected for at least one physical quantity (P, f) of the energy distribution network (2) with a detection speed and/or detection accuracy which are greater than specified limit values for a minimum detection speed and detection accuracy of the physical quantity (P, f), and the electric power transfer between the battery power plant (1) and the energy distribution network (2) is determined by taking account of the difference between the actual and the specified control speed and control accuracy of the physical quantity (P, f) to be controlled as well as a difference between the actual and the specified height and rate of change of the power transfer between the battery power plant (1) and the energy distribution network (2).

Abstract: A parallel generator system wherein a portion of the electrical load of at least one generator unit is incrementally transferred to at least one other generator unit by the controller on the basis of an indication that the operating stresses of the generator units are disallowably unbalanced, whereby load share balancing tending towards equalization of operating stresses amongst the plurality of generator units occurs over the system service life. Also, a method for load share balancing in a parallel generator system which determines whether the operating stress levels of at least two generator units are disallowably unbalanced by comparing operating stress indicators of the generator units with that of a master generator unit, and incrementally transferring portions the electrical load between at least two generator units on the basis of the comparative evaluation, whereby load share balancing occurs tending to equalize the generator unit operating stress levels.

Abstract: A power supply and demand control method for a power storage system includes predicting a consumption power of a customer for each of time slots divided by a specific time interval, assigning one of a frequency control or a peak shaving control to each of the time slots based on the predicted consumption power, controlling the storage battery based on the assigned frequency control or the assigned peak shaving control in each of the time slots, wherein the peak shaving control is assigned to each of the time slots in which the predicted consumption power is higher than a contract power, and the frequency control is assigned to each of the times slot in which the predicted consumption power is equal to or lower than the contract power.

Abstract: A method and system for eliminating the low-frequency oscillation between generators. By way of measuring the absolute rotor angle of a generator and controlling the rotor rotational speed, the absolute rotor angles obtained through measurement are the same when each GPS pulse per second signal arrives. The absolute rotor angles are angles of the internal potential Eq of the generator leading a GPS reference vector. Through the absolute rotor angle, zero steady state error control of the frequency and the rotor angle is achieved and the position of the generator rotor can remain unchanged in the PPS determined rotating coordinate system, thus suppressing the low-frequency oscillation better even without the need of remote measurement and achieving automatic local balance of active power during variation of loads. Accordingly, the power fluctuation on transmission lines is decreased while safe and stable operation of a large-scale interconnected power grid is achieved.

Abstract: An average load current calculator circuit configured for determining an average load current within an at least one phase switch mode power converter (SMPC) having at least one peak/valley detector receives an inductor current sense signal and determines and holds a peak or valley amplitude of the inductor current sense signal. A current corrector circuit receives an input voltage and an output voltage of the SMPC and an inductance value of the inductor of the SMPC for determining an average correction current of the peak or valley amplitude of the current sense. An average current generator receives the peak or valley amplitude of the current sense signal and the average correction current for determining the instantaneous average load current within a switch mode power converter (SMPC) by additively combining the peak or valley amplitude of the current sense signal and the average correction current.

Abstract: The disclosure is generally directed to reactance modules or DSRs (30) that may be mounted on a power transmission line (16) of a power transmission system (400). A DSR (30) may be configured in a bypass mode or in an injection mode (where reactance is injected into the corresponding line (16)). Multiple DSRs (30) installed on a power line section (18) define an array (410) and have a dedicated controller (440). Such an array (410) and controller (440) may be installed on a number of different power line sections (18). The controller (440) for each array (410) may communicate with a DSR server (420), which in turn may communicate with a utility-side control system (430). Each DSR (30) may incorporate one or more features directed to core (50) configurations and assembly, communications, modal configuration control, fault protection, EMI shielding, DSR (30) assembly, and DSR (30) installation.

Abstract: The present invention relates to a power conditioning unit for delivering power from a dc power source to an ac output, particularly ac voltages greater than 50 volts, either for connecting directly to a grid utility supply, or for powering mains devices independent from the mains utility supply. We describe a power conditioning unit for delivering power from a dc power source to an ac mains output, the power conditioning unit comprising an input for receiving power from said dc power source, an output for delivering ac power, an energy storage capacitor, a dc-to-dc converter having an input connection coupled to said input and an output connection coupled to the energy storage capacitor, and a dc-to-ac converter having an input connection coupled to said energy storage capacitor and an output connection coupled to said output, wherein said energy storage capacitor has a capacitance of less than twenty microfarads.

Abstract: A method and apparatus for power conversion. In one embodiment, an apparatus includes a power conversion module for converting a first current to a second current, where the first current or the second current is an AC current having at least two phases. The apparatus also includes a waveform modification module, coupled to the power conversion module, for modifying the AC current to generate a modified AC current, where each phase of the modified AC current has a value of zero at the beginning of an AC line cycle.

Abstract: A method for obtaining a continuous power flow of an electric power system is provided. The method uses the bus having the fastest voltage drop as the local parameterization bus, defines a slope of a line determined by the voltage of the geometric parameterization bus and the load growth factor as the parameterization variable, and adds a one-dimensional geometric parameterization constraint equation near turning points to obtain a nonsingular extended power flow equation, such that the continuation power flow can cross the turning points and a continuous P-V curve can be drawn reliably.

Abstract: This technology relates to systems and methods for effective selection of disparate distributed power sources for smart grid in near real time manner to meet the specific power demand. Power from the plurality of disparate power sources is received and then one or more power sources among the plurality of disparate power sources are selected based on one or more predefined requirements. At least one effective power source is determined from the one or more power sources by applying one or more algorithm based on number and range of the one or more power sources. The one or more algorithm comprise Complete Karmarkar Karp (CKK), pbrute, Heuristic based pbrute. A signal for selection of the at least one effective power source is generated and the signal is sent to a circuit switcher to supply the power from the at least one effective power sources to the smart grid.

Abstract: A double fed induction generator (DFIG) converter, methods and computer readable mediums are presented in which rotor side current spikes are attenuated by selectively activating at least one series damping circuit to conduct current through a series damping circuit resistance coupled in series between one or more DFIG rotor leads and a grid side converter in response to a grid fault occurrence or a grid fault clearance, and selectively bypassing the series damping circuit resistance after activating the series damping circuit.

Abstract: The present invention relates to an apparatus and method for performing adjustment to optimize the voltage for each distribution network in a power distribution system. The apparatus for adjusting a voltage in the power distribution system adjusts the voltage by switching a switch that lies on a path in the power distribution system. The apparatus determines a switch that is to become a switching target from among switches lying on the path, obtains a voltage optimization value of the determined switching target switch, selects a switch having the minimum voltage optimization value by changing the switching target switch to another switch in order to obtain the voltage optimization value, and adjusts the voltage through switching of the selected switch.

Abstract: A system having voltage regulator bypass means provides a means for preventing a voltage regulator to be bypassed in a power system when the difference between a load side voltage of the voltage regulator and a source side voltage of the voltage regulator is not below a certain threshold or substantially small. A voltage regulator controller can also prevent the voltage regulator from being bypassed when a tap changer of the voltage regulator is not in a neutral position.

Abstract: The disclosure relates to an electric power conversion apparatus, and capable of determining a minimum output voltage of a boost converter based on a voltage of the grid, and comparing the minimum output voltage of the converter with an input voltage of the converter, and controlling the operation of the converter based on the comparison result, thereby reducing the unnecessary operation and switching loss of the converter, the electric power conversion apparatus according to the invention comprises a converter; and a control unit configured to detect a grid voltage to determine a minimum output voltage of the converter based on the grid voltage, and control the operation of the converter based on an input voltage of the converter and the determined minimum output voltage.

Abstract: A control system for an energy storage device is coupled to sensors on an electrical grid. The control system is configured to receive a measurement from each of the sensors. The control system determines, based on the received measurements, whether a grid event is a local event or a distributed event. The control system selects a response mode for controlling the energy storage device based on whether the grid event is determined to be a local event or a distributed event.

Abstract: An improved power distribution network comprises a substrate, an integrated circuit mounted on the substrate, first and second tunable decoupling capacitors mounted on the substrate, and a third decoupling capacitor formed in the integrated circuit. The power supply pin is connected to the first, second, and third capacitors; and the first and second capacitors are connected to the third capacitor as well. The capacitance values of the first and second tunable decoupling capacitors may be adjusted to reduce the magnitude of the system level impedance at least at those frequencies having substantial signal jitter to power noise sensitivity.

Abstract: The present disclosure includes programmable snubber circuits and methods. In one embodiment, a circuit is configured between first and second power supply terminals. A programmable snubber circuit may be configured between the first and second power supplies to reduce ringing on the power supplies. In one embodiment, the circuit is a switching regulator and the power supply terminals are internal power supply terminals. The snubber circuit may be programmed to reduce ringing caused by switching currents through parasitic inductances in a package.

Abstract: Method and apparatus for mitigating SSR in power transmission system are provided. The method comprises: checking whether the sub-synchronous resonance (SSR) happens in the power transmission system; checking whether the sub-synchronous resonance is undamped; providing a command to bypass the SC unit when the SSR happens and is undamped. In some embodiments, the method further comprises providing a command to reinsert the SC unit into the power transmission system when the transmission level of the power transmission system is determined to be higher than a predetermined level and there is no fault in the power system. The invention also relates to a corresponding apparatus which can implement the method of the invention.

Abstract: Method and apparatus for automatic stabilization of an electric power supply network system comprising a network and at least one converter adapted to exchange maximum transferrable power with the network by changing the real current through a stabilizing controller, whereby the necessary direction of current change is determined through real-time stability analysis.

Abstract: A method of damping power system oscillations includes obtaining an AC measurement signal from a power system location and determining oscillation frequency values in the AC measurement signal. A plurality of single signal components are extracted from the AC measurement signal by subtracting a plurality of processed measurement signals from the AC measurement signal and a damping signal is generated based on the plurality of single signal components. Each of the plurality of processed measurement signals are generated by time delaying the AC measurement signal with a time delay associated with each of the oscillation frequency values other than the oscillation frequency value of the single signal component to be extracted.

Abstract: An electric vehicle supply equipment may include a first cover element including a well portion to accommodate a first circuitry, wherein the first circuitry includes a chimney stack that couples to a venting hole. Also, the electric vehicle supply equipment may include a second cover element including a recess portion to accommodate a second circuitry, wherein the second circuitry includes a charcoal filter that couples to the chimney stack to absorb impurities generated by the first circuitry and the second circuitry. Further, the electric vehicle supply equipment includes a universal/serial connection port configured to couple to peripheral devices, wherein the universal/serial connection port is an optical coupled connection.

Abstract: A method and system for detecting an islanding condition in a grid is provided. The method comprises detecting a potential islanding condition in a grid; and, in response to the detected potential islanding condition, ramping up an amount of reactive power, active power, or a combination of active and reactive power that is generated from a power conversion system until the earlier of the power conversion system shutting down or a threshold condition being reached.

Abstract: A system for damping power system oscillation includes a damping device controller for generating a damping control signal to compensate for a plurality of oscillation modes in the power system oscillations and a damping device to generate a damping signal based on a damping control signal. The damping device controller includes a plurality of outer closed loop paths each including an adaptive controller configured to determine an individual oscillation mode from at least one power system measurement signal. Each adaptive controller is further configured to generate an adaptive control signal to shift at least one open loop pole of an inner loop path related to the individual oscillation mode to a closed loop location.

Abstract: A system and a method for compensating harmonic components or a reactive power of an electrical network. The system comprises a measurement unit (1) configured to measure an electrical quantity to be compensated, a control unit (2) configured to determine harmonics contents or a reactive power need of the measured electrical quantity to be compensated as well as to determine, as relative values, desired values corresponding with the harmonics to be compensated or the reactive power to be compensated, one or more compensation units (5, 6) configured, responsive to the desired values provided by the control unit (2), to generate harmonic components or a reactive current according to the desired values given as relative values, and a communications connection (3) configured to communicate the desired values determined by the control unit (2) to the compensation units (5, 6).

Abstract: In one embodiment, a power conversion system includes a controller to provide power control to a converter, and a distortion mitigation circuit. In another embodiment, a system includes a converter to transfer power between a power source and a load having fluctuating power demand, and a controller to provide power control, where the controller may selectively disable the power control. In another embodiment, a power conversion system includes a controller to generate a drive signal to provide power control to a power path in response to a sense signal from the power path, where the sense signal is taken from other than the input of the power path, or the drive signal is applied to the power path at other than a first power stage.

Abstract: A control system for an energy storage device is coupled to sensors on an electrical grid. The control system is configured to receive a measurement from each of the sensors. The control system determines, based on the received measurements, whether a grid event is a local event or a distributed event. The control system selects a response mode for controlling the energy storage device based on whether the grid event is determined to be a local event or a distributed event.

Abstract: A method for controlling power flow within a multi-terminal DC power transmission system including two or more converter stations and the corresponding multi-terminal DC power transmission system are provided. The method includes the steps of: controlling the power flow to a steady state reference operating point for operating points within a control dead band defined for each respective converter station, and controlling the power flow by means of droop control in at least one of the converter stations upon detection of exceeding of an end point of one or more of the control dead bands.

Abstract: An improved power distribution network comprises a substrate, an integrated circuit mounted on the substrate, a first tunable decoupling capacitor mounted on the substrate, and a second tunable decoupling capacitor formed in the integrated circuit. The power supply pin is connected to both the first and second capacitors by a low frequency path and a DC path, respectively, and the first and second capacitors are connected by a high frequency path.

Abstract: A method, device and computer program product for providing improved control of power or voltage oscillation damping in a power transmission system. The device includes a magnitude obtaining element configured to obtain an instantaneous magnitude of a signal representing a deviating oscillation in at least one element of the power transmission system, a slope investigating element configured to determine the rate of change of the signal, and a first processing block including an integrating element configured to integrate the instantaneous magnitudes with an integrating factor that is based on the determined rate of change. The first processing block is further configured to form a phase compensation angle based on the integrated instantaneous magnitude for use in a damping control signal generating unit in order to provide power or voltage oscillation damping of the system.

Abstract: A device is configured to inject signals onto a medium made up of conductors and a reference plane. Transformers inject the signals onto the conductors by orthogonal modes. Differential mode chokes each include one input and two outputs. The input is connected to one end of a secondary winding of one of the transformers, or one of the outputs of another one of the chokes. The two outputs are connected to either the inputs of two others of the chokes, the input of another one of the chokes and a conditioner of one of the conductors, or conditioners of two of the conductors. The number of chokes depends on a number of non-differential modes used. The injections that use the chokes are injections selected from between pseudo-differential injections, injection in common mode, or a combination of pseudo-differential injections and injection in common mode.

Abstract: A power conversion system is described. The power conversion system includes a first power converter coupled to an electrical grid at a first point of interconnection (POI), a first processing device coupled to the first power converter and configured to control operation of the first power converter, and a first power measurement device coupled to the first processing device and configured to collect data associated with power output of the first power converter. The power conversion system also includes a first global positioning system (GPS) receiver coupled to the first processing device and configured to receive location information corresponding to a location of the first power converter and temporal information corresponding to a time at the location.

Abstract: System, method, and computer program product for dampening oscillations of the electrical power on a power grid. The system includes a wind park with multiple wind turbines. Each wind turbine includes a rotor, a generator operatively coupled with the rotor for generating electrical power, and an inverter coupling the generator with the power grid to output the electrical power to the power grid. A controller is configured to generate a first control signal to cause the inverter of the first wind turbine to modulate the electrical power output by the first wind turbine for dampening oscillations of one frequency in electrical power on the power grid and to generate a second control signal to cause the inverter of the second wind turbine to modulate the electrical power output by the second wind turbine for dampening oscillations of a different frequency in the electrical power on the power grid.

Abstract: A method, apparatus and system for suppressing low frequency oscillation in a power system. The method comprises: determining a system transfer function of an interconnected power system section in which a variable frequency transformer (VFT) is located; determining a damping controller parameters according to the system transfer function; and suppressing low frequency oscillation of the power system by means of the VFT based on the damping controller parameter. The objects of the method, apparatus and system are definite: optimizing the damping controller parameter can be achieved by simply tracking and analyzing the response of the system to disturbance, without the need to understand the configuration and parameters of the system or solve complicated power system equations, which has a better effect in suppressing low frequency oscillation in the power system and is advantageous for improving the safety and stability level of the power grid.

Abstract: A power oscillation damping controller is provided for a power generation device such as a wind turbine device. The power oscillation damping controller receives an oscillation indicating signal indicative of a power oscillation in an electricity network and provides an oscillation damping control signal in response to the oscillation indicating signal, by processing the oscillation damping control signal in a signal processing chain. The signal processing chain includes a filter configured for passing only signals within a predetermined frequency range.

Abstract: A method of damping power system oscillations includes obtaining an AC measurement signal from a power system location and determining oscillation frequency values in the AC measurement signal. A plurality of single signal components are extracted from the AC measurement signal by subtracting a plurality of processed measurement signals from the AC measurement signal and a damping signal is generated based on the plurality of single signal components. Each of the plurality of processed measurement signals are generated by time delaying the AC measurement signal with a time delay associated with each of the oscillation frequency values other than the oscillation frequency value of the single signal component to be extracted.

Abstract: In compensating for unbalanced voltages of three-phase AC, instantaneous values of wye-phase voltages 120° out of phase with each other are obtained from line voltages using a centroid vector operation, symmetrical component voltages of three-phase balanced system are obtained from the instantaneous values of wye-phase voltages, a compensation signal to compensate unbalanced voltages of three-phase AC is generated from zero-phase-sequence voltage of symmetrical component voltages is generated, wye-phase voltages 120° out of phase, the unbalanced voltages of which are compensated, are obtained from the compensation signal and the symmetrical component voltages, a control signal of a PWM conversion is generated based on the compensated wye-phase voltage compensated, and the unbalanced voltages of three-phase AC are compensated. The amount of time to compensate the three-phase unbalanced voltages required for detecting an unbalance of voltages and generating a control signal can be shortened.

Abstract: A power compensator for an electric power transmission line. The power compensator includes a voltage source converter, a capacitor and an energy storage device. The energy storage device includes a high voltage battery having a short circuit failure mode, a first main switch and second main switch for disconnecting the battery from the capacitor, and a control unit for operating the first and second switch.

Abstract: A method for avoiding electrical resonance in a vehicle having a high-voltage (HV) direct current (DC) bus shared by a first and a second power electronic converter device, such as an air conditioning compressor module (ACCM) and a traction power inverter (TPIM), includes determining an impedance characteristic of the bus, defining resonance points for the bus, selecting lower and upper switching frequency boundaries for the TPIM, and preventing the TPIM from operating within a range defined by these boundaries. A vehicle includes the first and second power electronic converter device, e.g., the APPM and the TPIM, the shared HV DC, and a controller having the algorithm set forth above, wherein the controller is adapted for avoiding electrical resonance in the HV DC bus by executing the algorithm.

Abstract: A power source stabilization circuit provided within a chip of an electronic device is provided. The power source stabilization circuit stabilizes a power source voltage supplied to an operational circuit of the electronic device. The power source stabilization circuit includes an amplifier that detects a fluctuation component in the power source voltage occurring in a main power source wiring used to supply the power source voltage to the operational circuit, amplifies the detected fluctuation component, and outputs the amplified fluctuation component, and a stabilization capacitor that is provided between an output end of the amplifier and the main power source wiring and supplies to the main power source wiring a current to reduce fluctuation in the power source voltage occurring in the main power source wiring, in accordance with the output from the amplifier.