Abstract: A device for measuring an amount of capacitance to correct a power factor of a running electric motor includes a three-phase bus for connection to the electric motor; a metering device operably connected to the three-phase bus for displaying KVAR, the metering device including a display for displaying power factor, voltage, current, frequency, active energy, reactive energy, active power, reactive power, apparent power or maximum demand of the motor; a plurality of switched delta-configured capacitor circuits operably connected to the three-phase bus, each of the switched delta-connected capacitor circuits having different capacitance values; and a plurality of switches, each of the switches being operably associated with a respective one of the switched delta-configured capacitor circuits to connect to the three-phase bus the respective one of the switched delta-connected capacitor circuit to minimize the KVAR reading.

Abstract: A wireless power supply apparatus generates an electric signal frequency-modulated or otherwise phase-modulated according to a transmission-side code that is determined beforehand with a wireless power reception apparatus. The electric signal thus generated is transmitted via a transmission coil so as to generate an electric power signal including any one of an electric field, a magnetic field, and an electromagnetic field. The wireless power reception apparatus receives the electric power signal using a reception coil. A control unit changes the impedance of a resonance circuit that comprises the reception coil and a resonance capacitor, according to a reception-side code that is to correspond to the transmission-side code.

Abstract: A method and apparatus for improving power generation in a thermal power plant. A dynamic reactive compensation system is provided and is connected to a high voltage bus or a generator bus of the power plant. The dynamic reactive compensation system comprises power electronic devices and is operable to provide most of the reactive power that is required from the power plant.

Abstract: Disclosed herein are various embodiments of systems and methods for controlling a voltage profile delivered to a load in an electric power system. According to various embodiments, an electric power system may include an electric power line, a variable tap transformer, and a capacitor bank. The variable tap transformer may include a plurality of tap positions. A tap change controller may be coupled with the variable tap transformer and may control the tap positions of the variable tap transformer. A capacitor bank controller may be coupled with the capacitor bank and may selectively couple the capacitor bank to the electric power line. The tap change controller and the capacitor bank controller may share system information related to the voltage profile along the electric power line and to change the voltage profile along the line using the variable tap transformer and the capacitor bank depending on the system information.

Abstract: A power transmitting apparatus for digitally controlling voltage and current of alternating current (AC) includes an input part, an output part, and a digital control part. The input part has a filtering protection module and a semiconductor switch module connected to the filtering protection module. The filtering protection module has an input interface for inputting an AC signal from a power source. The output part has a filtering module and a voltage and current feedback module connected to the filtering module. The voltage and current feedback module has an output interface for outputting the AC signal from the input part. The filtering module is connected to the semiconductor switch module of input part. The digital control part has a MCU control module electrically connected to the filtering protection module, the semiconductor switch module, and the voltage and current feedback module, respectively.

Abstract: There are provided a power factor correction circuit capable of transferring extra power to a ground before performing switching for a power factor correction to thereby reduce a switching loss generated in switching for a power factor correction, and a power supply device and a motor driving device having the same. The power factor correction circuit includes: a main switch switching input power to adjust a phase difference between a current and a voltage of the input power; and an auxiliary switch switched on before the main switch is switched on, to thereby form a transmission path for extra power of the main switch.

Abstract: A communications system includes a communications device having a plurality of access modules each having a port and connected to a communications line and a plurality of transmitters with the respective transmitter associated in one-to-one correspondence with the communications line of an access module. Each transmitter has a line driver and is configured to couple communications signals to a respective communications line. A voltage source is connected to the line drivers and configured to provide a bias voltage to the line drivers that varies depending on a selected minimum power level. A controller is connected to the voltage source and has logic configured to change the bias voltage to the line drivers. The controller is responsive to a minimum data rate for each bias voltage.

Abstract: A controller for controlling power to a light source includes a first sensing pin, a second sensing pin, a third sensing pin, and a driving pin. The first sensing pin receives a first signal indicating an instant current flowing through an energy storage element. The second sensing pin receives a second signal indicating an average current flowing through the energy storage element. The third sensing pin receives a third signal indicating whether the instant current decreases to a predetermined current level. The driving pin provides a driving signal to a switch to control an average current flowing through the light source to a target current level. The driving signal is generated based on one or more signals selected from the first signal, the second signal and the third signal.

Abstract: A digital power factor correction device is provided, which is an all-digital control module. The digital power factor correction device includes a voltage loop control unit, an input power control unit, a current loop control unit, and a pulse width modulation generation unit, to perform power factor correction for minimizing the phase difference between input current and input voltage through adjusting input current with an external driver and a switch unit. The voltage loop control unit and the current loop control unit contain a proportion-integral-differentiation controller to form a voltage control loop and a current control loop, respectively. The input power control unit adjusts current waveform according to the input power, while the pulse width modulation generation unit determines the stop time of pulse width modulation to produce a pulse width modulation signal, to control the external driver and the switch unit for eliminating loading effect.

Abstract: An adaptive dc-link voltage controlled LC coupling hybrid active power filter (LC-HAPF) for reactive power compensation includes: two dc capacitors to provide dc-link voltage; a three-phase voltage source inverter to convert dc-link voltage into compensating voltages; three coupling LC circuits to convert compensating voltages into currents; and an adaptive dc voltage controller with reactive power compensation control algorithm. The control algorithm includes: first, calculating required minimum dc-link voltage in each phase with respect to loading reactive power; three-phase required minimum dc-link voltage will be maximum one among their minimum values; compare it with predetermined voltage levels to determine final reference dc-link voltage. A dc-link voltage feedback P/PI controller outputs dc voltage reference compensating currents. An instantaneous power compensation controller outputs reactive reference compensating currents. The final reference compensating currents will be sum of them.

Abstract: The present invention relates to a control system and an associated method for controlling an amount of reactive power delivered from a wind power plant to an associated power supply grid, the control system comprising a wind power plant controller and a number of wind turbine controllers each being in communication with said wind power plant controller, wherein the wind power plant controller is adapted to provide a grid voltage reference in response to a required total amount of reactive power to at least one wind turbine controller and operating a Switched Capacitor bank.

Abstract: A PFC signal generation circuit which generates a PFC signal to control a PFC circuit including a first inductor connected to a first switch and a second inductor connected to a second switch includes: a first control signal output circuit that outputs a first PFC signal to turn on the first switch at a zero current detection timing of the first inductor; a timing adjustment circuit that generates a control signal to turn on the second switch after waiting until a target timing, when a zero current detection timing of the second inductor is earlier than the target timing, and to turn on the second switch at a target timing in a subsequent cycle, when it is later than an allowable period from the target timing; and a second control signal output circuit that generates a second PFC signal to turn on the second switch according to a control signal.

Abstract: Systems and methods are disclosed herein to a power factor adjustor comprising: a power factor measurement unit configured to measure the power factor on an input line to a load and generate a power factor correction signal based on the measured power factor; and a power factor adjustment unit connected to the power factor measurement unit comprising: a fixed capacitor connected in series to a first switching device; and an adjustable element having a variable capacitance connected in parallel to the fixed capacitor and in series to a second switching device, wherein the overall capacitance of the power factor adjustment unit is adjusted by adjusting the capacitance of the adjustable element or by toggling the first and second switching devices in response to the power factor correction signal.

Abstract: A first SVC is connected to a first bus. A first SVC control unit controls the first SVC. A first fluctuation-component-voltage generating unit includes a voltage reference circuit that outputs a voltage reference value. A second SVC is connected to a second bus. A second SVC control unit controls the second SVC. A second fluctuation-component-voltage generating unit includes a first-order-lag control block with limiter that generates a comparative voltage that follows a bus voltage of the second bus with a predetermined time lag characteristic and is limited within a predetermined range. An impedance value XS1 of slope reactance of the first SVC is set smaller than impedance value XS2 of slope reactance of the second SVC.

Abstract: A method of controlling a static VAR compensator includes providing a static VAR compensator having a capacitive component and a thyristor for switching the capacitive component into and out of a power distribution network; monitoring an electrical characteristic associated with the capacitive component; and controlling operation of the thyristor at least in part on the basis of the electrical characteristic associated with the capacitive component.

Abstract: The invention relates to an on-load tap changer comprising semiconductor switching elements for uninterrupted switching between fixed tap changer contacts which are electrically connected to winding taps of a tapped transformer. Each of the fixed tap changer contacts can be connected to a charge diverter either directly or, during switching, via the semiconductor switching elements that are connected therebetween. According to the invention, the charge diverter has fixed, divided diverting contact pieces in order for the semiconductor switching elements to be electrically isolated from the transformer winding during stationary operation.

Abstract: A controller for controlling power to a light source includes a first sensing pin, a second sensing pin, a third sensing pin, and a driving pin. The first sensing pin receives a first signal indicating an instant current flowing through an energy storage element. The second sensing pin receives a second signal indicating an average current flowing through the energy storage element. The third sensing pin receives a third signal indicating whether the instant current decreases to a predetermined current level. The driving pin provides a driving signal to a switch to control an average current flowing through the light source to a target current level. The driving signal is generated based on one or more signals selected from the first signal, the second signal and the third signal.

Abstract: A device for improving efficiency of an induction motor soft-starts the motor by applying a power to the motor that is substantially less than the rated power of the motor then gradually increasing the power while monitoring changes in current drawn by the motor, thereby detecting when maximum efficiency is found. Once maximum efficiency is found, the nominal motor current is found and operating ranges are set. Now, the phase angle between the voltage and the current to the motor is measured and power to the motor is increasing when the phase angle is less than a minimum phase angle (determined during soft-start) and power to the motor is decreased when the phase angle is greater than or equal to the minimum phase angle as long as the voltage does not fall below a minimum voltage determined during soft-start.

Abstract: Disclosed herein are various embodiments of systems and methods for controlling a voltage profile delivered to a load in an electric power system. According to various embodiments, an electric power system may include an electric power line, a variable tap transformer, and a capacitor bank. The variable tap transformer may include a plurality of tap positions. A tap change controller may be coupled with the variable tap transformer and may control the tap positions of the variable tap transformer. A capacitor bank controller may be coupled with the capacitor bank and may selectively couple the capacitor bank to the electric power line. The tap change controller and the capacitor bank controller may share system information related to the voltage profile along the electric power line and to change the voltage profile along the line using the variable tap transformer and the capacitor bank depending on the system information.

Abstract: A method and system for aggregating messages. In one embodiment, the system comprises a plurality of distributed generators (DGs) and a controller, communicatively coupled to the plurality of distributed generators, for (i) receiving a plurality of messages from the plurality of DGs, (ii) correlating at least two messages in the plurality of messages based on at least one time parameter, and (iii) generating a summary message based on the at least two messages.

Abstract: Assemblies for HVAC systems and methods of operating HVAC systems are disclosed, including a method of operating an HVAC system having a condenser motor operatively coupled to a fan and a controllable bus voltage for powering the condenser motor. The method includes increasing the controllable bus voltage from a first voltage to a second voltage to increase a speed of the condenser motor.

Abstract: A system and method for dynamically adjusting capacitance added in parallel to an electrical line input for improving efficiency of an electrical system. A microprocessor monitors in real time the current and voltage wave forms of a system and selects the optimum amount of capacitance from a bank of capacitors of different values. The system is implemented at the utility transformer to encourage adoption of the device by utility companies and customers.

Abstract: A digital controller for a power factor correction (PFC) circuit, has first means for generating a first control signal for a switching transistor to avoid continuous oscillation between an inductor and parasitic capacitance of the switching transistor during discontinuous mode operation when an input voltage is less than substantially 50% of an output voltage. Second means generates a second control signal for a switching transistor to avoid continuous oscillation between an inductor and parasitic capacitance of the switching transistor during discontinuous mode operation when an input voltage is greater than substantially 50% of an output voltage. A power factor correction circuit and a method of operating a power factor correction circuit are also disclosed.

Abstract: A device for improving efficiency of an induction motor that soft-starts the motor by applying a voltage to the motor that is substantially less than the rated voltage then gradually increasing the voltage while monitoring changes in current drawn by the motor, thereby detecting when maximum efficiency is found. Once maximum efficiency is found, the nominal motor current is found and operating ranges are set. Now, the voltage to the motor is increased/decreased by measuring the phase angle between the voltage and the current to the motor and increasing the voltage when the phase angle is less than a minimum phase angle (determined during soft-start) and decreasing the voltage when the phase angle is greater than or equal to the minimum phase angle as long as the voltage does not fall below a minimum voltage determined during soft-start.

Abstract: A capacitor bank unit includes three capacitor banks that have respective capacitances that are multiples of a basic capacitance in accordance with a number sequence of the n-th power of 2. One of the capacitor banks has the basic capacitance, remaining two of the capacitor banks includes two subbanks each. The capacitance of a subbank is set to a capacitance that is a multiple of the basic capacitance in accordance with a number sequence of the m-th power of 2. When any one of the capacitor banks fails, each of capacitor banks following the failed capacitor bank substitutes for a capacitor bank located immediately before itself.

Abstract: A one cycle control method for power factor correction based on a boost circuit and a main control chip of system comprises the steps of: (1) Determining whether soft-start ends or not; if the soft-start ends, processing step (2) directly, if not, increasing reference value Uref of output voltage and then processing step (2); (2) Reading sampling output voltage Uo, and sampling inductive current ig according to A/D sampling triggering instant; (3) Calculating duty ratio of PWM signal for driving the switch transistor; (4) Outputting PWM signal; (5) Calculating the next A/D sampling triggering instant according to the duty ratio of PWM signal; (6) Returning to step (2).

Abstract: A distributed capacitor bank controller for power factor correction of a power system may include a first distributed meter, a second distributed meter, a programmable logic controller and a communications pathway. The first and second meters may be operable to provide a power factor value, a current value, a voltage value, and a load value. The first and second meters may be coupled to the programmable logic controller via the communications pathway. The programmable logic controller may be operable to receive the power factor value, the current value, the voltage value and the load value from the first and second distributed meters, determine an average power factor value and a current unbalance value, and automatically add or remove a capacitor step of a capacitor bank to the power system based at least in part on the average power factor value, the current unbalance value, the voltage value and the load value.

Abstract: A system and method for dynamically adjusting capacitance added in parallel to an electrical line input for improving efficiency of an electrical system. A microprocessor monitors in real time the current and voltage wave forms of a system and selects the optimum amount of capacitance from a bank of capacitors of different values. The system is implemented at the watt-hour meter to encourage adoption of the device by utility companies and customers.

Abstract: A light source apparatus and a light source adjusting module are provided. The light source apparatus includes a power supply, a phase modulator, an electrical transformer, a light source adjusting module and a light-emitting device. The power supply provides a first AC voltage signal. The phase modulator receives the first AC voltage signal and adjusts a conducting phase of the first AC voltage signal to generate a modulated AC voltage signal. The electrical transformer transforms the modulated AC voltage signal to generate a second AC voltage signal. The light adjusting module generates a luminance adjusting signal according to a state of the second AC voltage signal. The light-emitting device receives the luminance adjusting signal to generate a corresponding light source.

Abstract: A method and system for aggregating messages. The method comprises obtaining, at a controller, a first plurality of messages related to operation of a distributed energy generator; generating, at the controller, a second plurality of messages from the first plurality, wherein each message in the second plurality has a start-time within a first time window; and generating, at the controller, a third plurality of messages from the second plurality, wherein each message in the third plurality has an end-time within a second time window and is associated with an indicia of a message group.

Abstract: Automated power factor correction analysis methods based on an automatically determined hierarchy representing how IEDs and transformers are linked together in an electrical system for reducing a utility bill, releasing capacity to the electrical system, reducing losses, and/or improving voltages. The automatically determined hierarchy places the system elements in spatial context and is exploited by the power factor correction analysis methods to identify power factor correction opportunities. Recommendations are made as to sizing and location of capacitors within the hierarchy where power factor improvements can be achieved. Harmonic distortion levels can be checked first to determine whether safe levels exist for capacitor banks. Recommendations are also checked to avoid leading power factors anywhere in the system due to the addition of capacitor banks. Capacitor bank location is tailored to the end-user's goal for power factor correction.

Abstract: The present invention relates to a power factor correction circuit and a driving method thereof. The power factor correction circuit refers to an inductor receiving an input voltage and supplying output power, a power switch connected to the inductor and controlling an inductor current flowing in the inductor, and an auxiliary coil coupled with the inductor with a predetermined turn ratio. The power factor correction circuit controls the output power by controlling a switching operation of the power switch, and counts the number of times that the inductor current reaches a predetermined maximum current to turn off the power switch when the count result reaches a predetermined short circuit threshold count.

Abstract: A method and apparatus for improving power generation in a thermal power plant. A dynamic reactive compensation system is provided and is connected to a high voltage bus or a generator bus of the power plant. The dynamic reactive compensation system comprises power electronic devices and is operable to provide most of the reactive power that is required from the power plant.

Abstract: A distributed capacitor bank controller for power factor correction of a power system may include a first distributed meter, a second distributed meter, a programmable logic controller and a communications pathway. The first and second meters may be operable to provide a power factor value, a current value, a voltage value, and a load value. The first and second meters may be coupled to the programmable logic controller via the communications pathway. The programmable logic controller may be operable to receive the power factor value, the current value, the voltage value and the load value from the first and second distributed meters, determine an average power factor value and a current unbalance value, and automatically add or remove a capacitor step of a capacitor bank to the power system based at least in part on the average power factor value, the current unbalance value, the voltage value and the load value.

Abstract: The present invention relates to a power factor correction circuit and a power factor correction method. The present invention receives information on an output voltage of output power and information on an inductor voltage to control a switching operation of a power switch, and estimates the input voltage according to duty of the power switch.

Abstract: A capacitor bank unit includes three capacitor banks that have respective capacitances that are multiples of a basic capacitance in accordance with a number sequence of the n-th power of 2. One of the capacitor banks has the basic capacitance, remaining two of the capacitor banks includes two subbanks each. The capacitance of a subbank is set to a capacitance that is a multiple of the basic capacitance in accordance with a number sequence of the m-th power of 2. When any one of the capacitor banks fails, each of capacitor banks following the failed capacitor bank substitutes for a capacitor bank located immediately before itself.

Abstract: A power switching control apparatus for acquiring pieces of making operation time information of individual phase switches more precisely according to loads and making instants. Making operation time information detecting means outputs the making operation time information of at least one of individual phase switches on the basis of the motion of the movable contact of the phase switch, and outputs the making operation time information of at least another of the individual phase switches on the basis of the phase current of the phase switch. Moreover, the making operation time information detecting means outputs the making operation time information ITA, ITB and ITC of an A-phase switch, a B-phase switch and a C-phase switch individually on the basis of either the detected output of a contact operation sensor and the detected output of a phase current sensor.

Abstract: A flicker improvement effect evaluating system evaluates an effect of improvement of voltage flicker in a power system to which a static reactive power compensator is to be introduced. A system voltage operating unit operates a compensation current and a system impedance of the power system, based on actually measured data of system voltage and load current read from a data reading unit. Based on the results of operations and the actually measured data, a not-yet-improved system voltage at present and an improved system voltage attained when the static reactive power compensator is provided on a bus are simulated. By a flicker meter, flicker values of the not-yet-improved system voltage and improved system voltage amplified by an amplifying circuit are measured, and from the flicker values, the rate of improvement attained by the static reactive power compensator is operated.

Abstract: A inverter has a switching device for switching DC to change it to AC, and a bipolar type rechargeable battery connected to the switching device in parallel or in series for smoothing the current from the switching device.

Abstract: Systems and methods for an inductive powering surface for powering portable devices are described. In one aspect, a powering device includes the inductive powering surface. The inductive powering surface includes multiple primary coils, an impedance auto-match circuit and other control circuits. The impedance auto-match circuit selectively energizes the primary coils to transfer power via inductive coupling to the secondary coil(s) in a portable device. The impedance auto-match circuit is configured to detect voltage and current phase differences over caused by positioning of the portable device on the inductive powering surface. The impedance auto-match circuit calibrates a power factor of the inductive powering surface to transfer an objectively maximized power load via inductive coupling to the portable device.

Abstract: A reactive power compensator includes a control block with a limiter and a primary delay-control block with a limiter that set, based on an output of a voltage sensor, reactive power produced by an SVC to a predetermined value. A reactive power controller sets the reactive power produced by the SVC to the predetermined value controls a voltage of a second bus to fall within a predetermined range. This is performed by adjusting an initial value of the reactive power that is output by the SVC, when a bus voltage of the second bus laid at a position apart from a first bus that is laid at a position near the SVC is deviated from a predetermined fixed range.

Abstract: An apparatus for controlling a power flow in a high voltage network. A phase shifting transformer includes a tap changer.

Abstract: An external AC power adaptor having an additional compartment for cooling. The adaptor has a housing that defines a first compartment having power circuitry for converting an AC input to a DC output and a second compartment that has an opening formed in the adaptor housing. A heat transfer plate is disposed between the first and second compartments.

Abstract: A power supply margin controller may alter the voltage of a control signal used to control the output voltage of a power supply. The controller may include a digital-to-analog converter having an input and an output, and a comparator having a first input coupled to receive the control signal, a second input coupled to the output of the digital-to-analog converter, and an output. The controller may include a processing system configured to deliver data to the input of the digital-to-analog converter based on the output from the comparator that causes signals at the inputs to the comparator to be substantially equal.

Abstract: A four switch voltage converter is regulated for buck mode and boost mode under constant frequency valley-peak current mode control. Protection circuits are responsive to output voltage and regulator current to prevent excessive current that otherwise might result from abnormally low output voltage short circuit, or spurious switching abnormalities during low duty cycle operation. The regulator control circuit is responsive to the protection circuits to automatically connect a regulator inductor between a common potential and the output to limit current.

Abstract: To conserve power when regulating the output voltage (Vo) of a power converter, no adjustment is made to the converter's pulse width modulation times (Tp, Ts) even if the output voltage is off target (Vtar), provided that the output voltage does not change or is moving towards the target voltage. In some embodiments, the output voltage is not allowed to stay off target for more than a predetermined length of time. In some embodiments, the minimal adjustments are always large enough to overcome ringing (1004).

Abstract: An apparatus is provided to control a power voltage on a power-supplying line extending from a generator and connecting to a battery and eclectic loads. The apparatus is mounted on a vehicle and comprises a detecting device, a calculator, and a controller. The detecting device detects pairs of voltage and current of the battery. The calculator calculating a control current on the basis of the detected pairs of voltage and current and a target voltage for the power voltage. The pairs of voltage and current are used to calculate an internal resistance and/or a regression line of the battery. The controller controlling a charge and discharge current of the battery on the basis of the control current so that the power voltage is controlled to the target voltage.

Abstract: Provided is a digitally-controlled linear regulator having noise-shaped component selection. The digitally-controlled linear regulator has a regulated-voltage sensor, a comparator module, a quantization module, and an impedance switching network. The regulated-voltage sensor is operably coupled to sense an output voltage of the digitally-controlled linear regulator to produce a sensed output voltage. The comparator module is operably coupled to compare the sensed output voltage with a reference voltage at a predetermined clock rate to produce a digital regulation signal. The quantization module is operably coupled to quantize the digital regulation signal to produce a quantized regulation signal. The impedance switching network is operably coupled to convert a source voltage into the output voltage of the digitally-controlled linear regulator based on the quantized regulation signal.

Abstract: A static VAR compensator has several parallel compensation components (K1–K3). To connect the static VAR compensator to an operating voltage (U) the compensation components (K1–K3) are first successively connected to the operating voltage (U) by a control unit (CU) via a series resistor (R). The compensation components (K1–K3) are only connected to the operating voltage (U) without series resistance once the aforementioned connection has been completed.

Abstract: An apparatus has a green compact electrode including a material of a coating formed on a workpiece by a discharge, a power source for supplying a first voltage, a voltage detector for detecting a voltage between the workpiece and the electrode, and a pulse current generator for generating and outputting a pulse current from the first voltage, and for cutting off the output when a predetermined period of time has passed after the voltage is detected to be less than a detection voltage. The pulse current is supplied between the workpiece and the electrode, and the detection voltage is less than the first voltage by 5% to 20% of the first voltage.