Abstract: A switching DC to AC power converter includes an automatic zero voltage switching (ZVS) mode controller. The automatic zero voltage switching mode controller may adjust a ZVS dead-time in accordance with a range of load currents being supplied by the power converter that range from quiescent conditions to a predetermined loading level of the power converter. The variable ZVS dead-time may be larger nearer to quiescent conditions, and become progressively smaller as load currents increase. Outside a predetermined range of load currents, the variable ZVS dead-time may be disabled or minimized.

Abstract: A control apparatus of a single-phase power converter for a photovoltaic power generation system is disclosed, including a POS MPPT controller for calculating a rating current by applying a POS MPPT control method to an output current detected through a current transformer of a single-phase AC filter, a bandpass filter for filtering only signals of a low-frequency band from a load, a single-phase reference current generator for producing a reference current by matching a phase of the current from the POS MPPT controller to a phase from the bandpass filter, a single-phase current subtractor for subtracting an output current of a current transformer from the reference current calculated by the single-phase reference current generator to thereby calculate a difference current between the output current of the current transformer and the reference current, a PI controller for outputting a control signal, corresponding to the difference current from the single-phase current subtractor, to a PWM signal generator, a

Abstract: For the purpose of providing a resonant switching power supply device having a wide output voltage variable range by changing its switching frequency, the resonance circuit thereof comprises a switching transformer, a first resonance section connected in series with the switching transformer, and a second resonance section connected in parallel with the switching transformer, wherein the resonance frequency characteristic in the case that the DC load current is large is formed using the series-connected devices of the first resonance section, and the resonance frequency characteristic in the case that the DC load current is small is formed using the first resonance section, the second resonance capacitor of the second resonance section and the switching transformer.

Abstract: A method for driving a power bridge (1) which is used for controlling a multiphase electric load (3), connectable to said electric load (3) via several arms and drivable by switching functions which determine free wheel controlling vectors and are active for controlling the load. The inventive method consists in selecting a first switching function production method which produces a reduced number of combinations of switching functions corresponding to the free wheel control vectors or a second switching function production method which produces combinations of switching functions corresponding only to the active control vectors, wherein said method are defined according to a given reference voltage vector and in applying said selected for producing a sequence of control vectors from the produced combinations of switching functions.

Abstract: An AC power supply and a method for dynamically controlling the output current thereof are disclosed. An output voltage stop signal is used to disable a DC/AC converter from outputting. During a period that the DC/AC converter stops its output, the output current of the DC/AC converter is measured and is fed back to a output current control device as an output current feedback signal to produce a deviation. Using the difference between the output current feedback signal of the DC/AC converter and the deviation, an approximate DC value of the output current of the DC/AC converter is calculated. With reference to the approximate DC value, the DC/AC converter can be controlled so that the DC current injection in the output current is approximately zero.

Abstract: Voltage inverter provided with four switching cells (Q1 to Q4) to be connected to the terminals of a DC voltage source (Vdc), each comprising two semiconductor switches (I11, I12, I21, I22, I31, I32, I41, I42) installed in series, these switches having a common point (A0) to be connected to an AC current source (Mac) with three phases (p1, p2, p3) and a neutral (n), the connection being made onto one phase (p1, p2, p3) for three of the cells (Q1, Q2, Q3) and onto the neutral (n) for the fourth cell (Q4). Each cell (Q1 to Q4) cooperates with a semiconductor electrical isolating device (S1, (S2.1 and S2.2)) to be put into a turn-off state if the cell should fail, this isolating device (S1, (S2.1 and S2.2)) being arranged either on the connection to the AC current source (Mac), or on connections to the terminals of the DC voltage source (Vdc).

Abstract: A method for the startup of a solar power three-phase inverter in which a waiting period is increased between successive attempts to start the inverter. This method allows the inverter to start up in a reasonable amount of time while avoiding excessive cycling during prolonged periods of low light.

Abstract: A power converter delivers electrical power from an electrical power source to a load according to a plurality of operation modes, where at least one of the operation modes is a peak current switching mode. Under the peak current switching mode, a switch controller controls the switch in the power converter to be kept on until the current through the switch reaches a peak current value corresponding to a given phase of the input voltage signal to the power converter. The peak current values have a reference shape, which may be a trapezoidal. The power converter may have any topology, such as a flyback-type power converter or a boost-type power converter.

Abstract: A display apparatus includes a display panel and a backlight assembly including a lamp and an inverter. The inverter includes a main transformer, a main driver and a voltage controller. The main transformer applies a driving alternating current (AC) voltage to the lamp. The main driver generates an output signal controlling the main transformer based on a feedback signal from the main transformer. The voltage controller is electrically connected to a feedback terminal of the main driver to control a maximum level of a voltage applied to the feedback terminal.

Abstract: Distributed maximum power point tracking systems, structures, and processes are provided for power generation structures, such as for but not limited to a solar panel arrays. In an exemplary solar panel string structure, distributed maximum power point tracking (DMPPT) modules are provided, such as integrated into or retrofitted for each solar panel. The DMPPT modules provide panel level control for startup, operation, monitoring, and shutdown, and further provide flexible design and operation for strings of multiple panels. The strings are typically linked in parallel to a combiner box, and then toward and enhanced inverter module, which is typically connected to a power grid. Enhanced inverters are controllable either locally or remotely, wherein system status is readily determined, and operation of one or more sections of the system are readily controlled. The system provides increased operation time, and increased power production and efficiency, over a wide range of operating conditions.

Abstract: A digital controller for controlling the operation of a DC-DC switching converter is disclosed. A digital feedback control system is provided for receiving an analog input voltage representing the output of the switching converter and digitally processing the analog input voltage by comparing it to a reference voltage and then determining analog drive signals to control the operation of the switching converter to provide a regulated output. The digital feedback control system operates in accordance with predetermined operating parametrics. The digital feedback control system also has monitoring inputs and control inputs. A microcontroller monitors the operation of the digital feedback control system and is able to change the operating parametrics under certain predetermined conditions.

Abstract: An apparatus and method for controlling an inverter capable of enhancing reliability of current measurement by ensuring an optimal time for which effective voltage vectors are applied to detect a three-phase current according to a phase current and sizes of the effective voltage vectors, the apparatus comprising a space voltage modulator that generates and outputs effective voltage vectors based upon a voltage command value, and a low modulation determiner that determines whether the effective voltage vectors are located within a low modulation region, and outputs a low modulation switching control signal or a normal modulation switching control signal according to the determination.

Abstract: An output voltage detection circuit is provided for accurately detecting a secondary side output voltage based on a voltage induced to an auxiliary winding in an isolated switching power supply including a transformer having the auxiliary winding. A voltage waveform processing circuit (10-1) processes the waveform of the voltage induced to the auxiliary winding (7-3), a hold circuit (10-2) holds the voltage peak value after the processing, a secondary side current detection circuit (24) detects a period during which current passes through a secondary side winding (7-2), a correction circuit (22) performs correction to decrease the peak voltage which has been held by the hold circuit (10-2) during the period, and the corrected voltage is fed back to a control circuit (9). Meanwhile, a reset circuit (23) resets, for a fixed period after the current passes through the secondary side winding (7-2), the peak voltage having been held by the hold circuit (10-2).

Abstract: An exemplary inverter circuit (2) includes a full-bridge circuit (21) for converting a DC voltage into an AC low voltage, main inverse transformers (22) for converting the AC low voltage into an AC high voltage, and a feedback circuit (25). The feedback circuit includes a secondary inverse transformer (250) for converting the AC low voltage into an AC high voltage, a sampling unit (254) for sampling the AC high voltage and outputting a sampling voltage, and an integral circuit unit (205) for integrating the sampling voltage and outputting an integrated sampling voltage to the full-bridge circuit. When the AC low voltage outputted by the full-bridge circuit fluctuates, the feedback circuit sends a feedback voltage to the full-bridge circuit, and the full-bridge circuit stabilizes the AC low voltage according to the feedback voltage. The feedback voltage is in direct proportion to the fluctuation of the AC low voltage.

Abstract: The invention concerns a device for controlling a final power-output stage, the latter comprising three half-bridges consisting respectively of a series circuit including an upper semiconductor switch and a lower semiconductor switch and subjected to a service voltage, the connection points of the semiconductor switches of the half-bridges forming outputs which are connected to the windings of a motor having at least three phases. The invention is characterized in that there is provided a control device for shifting on-state respectively one semiconductor switch or simultaneously several semiconductor switches according to a predetermined programme and for determining whether the respective voltages at the outputs are respectively within a predetermined tolerance range for the corresponding switching state.

Abstract: A system for controlling a soft start for a switching power converter includes a digital controller that enables the programming of a plurality of input voltage profiles during a soft start condition of the switching power converter. The programming of the plurality of input voltage profiles is parameterized by a control parameter. A microcontroller determines the control parameter used by said digital controller and operates independently of the operation of the digital controller.

Abstract: Consistent with an aspect of the present disclosure, a method is provided for controlling an AC signal, which is supplied to a load and selectively supplied to a utility grid. In response to a fault in the utility grid, the method includes decoupling the AC signal from the utility grid, and determining whether a voltage associated with the AC signal is within a desired band. The method also includes adjusting the voltage associated with the AC signal when the AC signal is outside the desired band, and comparing a magnitude of a current associated with the AC signal with a desired current value to thereby obtain a comparison result. In response to the comparison result, the current associated with the AC signal is adjusted when the voltage associated with the AC signal is within the desired band.

Abstract: It is an object of the present invention to provide an operation control circuit without using a photo-coupler. The operation control circuit controls the operation of an LED in a DC/AC inverter comprising a voltage conversion circuit, a DC/AC conversion circuit for converting output voltage of the voltage conversion circuit to two pieces of AC voltage each with an opposite phase, and an LED which is lit when AC voltage is outputted from the DC/AC conversion circuit. The operation control circuit comprising a rectifier circuit, capacitors connected between the input terminal of the rectifier circuit and the output terminal of the DC/AC conversion circuit, and a comparator circuit connected to the same ground level as the ground level connected to the LED for lighting the LED when voltage V1 outputted from the rectifier circuit is higher than a threshold Vref1.

Abstract: Cycle error correction is performed in an electronic power system to compensate for a difference between an AC grid side frequency and an AC load side frequency. The electronic power system can comprise an electronic power inverter, such as one usable with an uninterruptible power supply. Cycles of signals indicative of the AC grid power and the AC load power are counted and compared to obtain a cycle error value. If the cycle error value exceeds a first value to indicate that AC load side frequency is too high or too low, then compensation is performed to change the AC load side frequency to be closer to the AC grid side frequency. If the cycle error value falls below a second value to indicate that the AC grid side frequency and AC load side frequency are sufficiently close to one another, then the compensation is deactivated.

Abstract: A value of an AC reference waveform is obtained and converted to a d-q reference frame value. A phase estimate is generated responsive to the d-q reference frame value. An AC output of the power supply apparatus is controlled responsive to an output current of the power supply apparatus and the phase estimate. For example, an output current value may be obtained and converted to a d-q reference frame current value responsive to the phase estimate, and the AC output may be controlled responsive to the d-q reference frame current value.

Abstract: The invention relates to a method for recognizing the operational state of a load (10) connected to the output (6,7) of an island inverter (1). A load recognition signal (SL) is applied at specific moments in time to the output (6, 7) of the island inverter (1), during which specific electric parameters are measured on the island inverter (1), enabling the operational state of the load (10) to be determined, wherein the island inverter (1), when the load (10) is activated, is switched from a possible standby mode into a permanent operation mode and, when the load is deactivated (10), the island inverter is switched from a possible permanent operation mode to a standby mode. The invention also relates to an island inverter (1). In order to ensure reliable recognition of all possible collected loads (10), a load recognition signal (SL) with parameters (T, d, A, H, f) that are modified at least according to the type of load (10) is applied to the output (6,7) of the island inverter (1).

Abstract: An inverter circuit and a control circuit thereof for converting DC power from the renewable energy or distributed energy into AC power so as to be fed into the AC utility power system according to related regulations. The inverter circuit comprises a buck-boost inverter, a DC-to-AC inverter comprising two half-bridge inverters, and a by-pass passive switch coupled to an input DC voltage and the positive terminal of a first DC voltage. The inverter circuit of the present invention prevents the switching loss of an active switch and the energy loss of a coupled inductor by use of the by-pass passive switch and improves the efficiency of the inverter circuit by use of voltage feed-forward compensation.

Abstract: An object of the present invention is to provide a photovoltaic power generation system which is capable of achieving system linkage of a plurality of solar cell strings having different output voltages to a commercial electric power system with ease, and which enables efficient use of the maximum output electric power. It is a photovoltaic power generation system characterized by disposing voltage regulating means that regulates a DC voltage outputted from non-standard solar cell string between a standard solar cell string and electric power converting means, and regulating an output voltage of the non-standard solar cell string to the side of an output voltage of the standard solar cell string by the use of the voltage regulating means.

Abstract: Substantially-accurate calibration of output impedance of a device-under-test (DUT) to within a predetermined range of allowable impedance. The DUT is part of a source series terminated (SST) serial link transmitter, in which two branches of parallel transistors each provide an impedance value when particular transistors of the parallel branch are turned on. The impedance value is added to a series-connected resistor to provide the output impedance. The DUT consists of one branch of parallel transistors in series with a resistor. Output impedance of the DUT is compared to the resistance of a reference resistor, and the comparator provides a control signal based on whether the output impedance falls within the pre-set percentage variance of the reference resistance. The control signal is processed by a FSM (finite state machine) that individually turns on or off the transistors within the parallel branch until the DUT impedance value falls within the desired range.

Abstract: A phase adjusting circuit is provided that is capable of adjusting a delay time at a rise or fall of a driving signal for driving an inverter. A phase adjusting circuit is provided upstream of a driver circuit, and an output from a hysteresis comparator is input to the driver circuit through the phase adjusting circuit. The phase adjusting circuit delays at least either rise or fall of the signal input to the driver circuit to adjust any difference between the pulse width of the input signal input to the driver circuit and the pulse width of a signal output from a switching element of an inverter driven by the driver circuit.

Abstract: Cycle error correction is performed in an electronic power system to compensate for a difference between an AC grid side frequency and an AC load side frequency. The electronic power system includes an electronic power inverter, such as one usable with an uninterruptible power supply. Cycles of signals indicative of the AC grid power and the AC load power are counted and compared to obtain a cycle error value. If the cycle error value exceeds a first value to indicate that AC load side frequency is too high or too low, then compensation is performed to change the AC load side frequency to be closer to the AC grid side frequency. If the cycle error value falls below a second value to indicate that the AC grid side frequency and AC load side frequency are sufficiently close to one another, then the compensation is deactivated.

Abstract: An inverter circuit according to an embodiment comprises an input unit to which a first voltage is applied, a transformer for transforming the first voltage output from the input unit, a first switching unit for switching an on/off state of the transformer, an inverter controller for controlling an operation of the first switching unit, an output unit for outputting a second voltage output from the transformer, a feedback unit for detecting an electrical signal from the transformer and supplying the detected electrical signal to the inverter controller, and an initial operation controller for controlling an intensity of the electrical signal supplied to the inverter controller from the feedback unit.

Abstract: Each time a system interconnection inverter is booted up, a control program, which is stored in a remote-controller, is downloaded and stored in a RAM in a main body side. When the system interconnection inverter is halted, the control program in the RAM is lost.

Abstract: A DC-AC inverter has an adjustment device for adjusting wave shape of output thereof includes a feedback circuit, and a zero-crossing detector; the feedback circuit will detect and measure output voltage of the inverter, and feedback-control the inverter to make the inverter output a demanded stable fixed voltage, thus preventing the output voltage of the inverter from changing owing to an input voltage and the loading effect caused by electric appliances connected thereto; the zero-crossing detector is used to detect and measure the frequency and wave shape of the output of the DC-AC inverter therefore the DC-AC inverter can be further connected in parallel to another DC-AC inverter or an utility grid when the feedback circuit is used to feedback-control the inverter for the inverter to provide a demanded stable fixed voltage output.

Abstract: The dc to ac power generator has a DC power source which is connected at one pole to the primary of a conventional voltage transformer, and at its other pole to a relay controlled switching system. A mechanical switch of the relay is connected to the opposite pole of the transformer primary and it also responds to the presence of voltage on the secondary windings of the transformer, i.e., when the relay is energized. Due to inherent time delays introduced by a combination of the transformer circuitry and the relay energizing circuitry, the relay switching system functions at precise and equal time intervals to reverse polarity of the DC power source with respect to the coils of the transformer, such that output power signals provided at the secondary of the transformer define a precise square wave configuration with waves of equal time duration and approximately equal and opposite magnitudes.

Abstract: An inverter for use in connecting a DC power source to the utility grid includes a single DC-AC conversion stage, maximum (source) power tracking, and current control based on feed-forward compensation as a function of input power voltage error, rectified utility line voltage, and a scaled inverse of RMS utility line voltage. Various topologies of the inverter power stage are developed for bi-directional power-flow operation after those developed for unidirectional power-flow operation. Various embodiments also include over-voltage protection, over-current protection, under-voltage protection, over-temperature protection, and stand-by battery with battery management control, while still others are adapted for a multiple-channel front-end distributed power system with distributed maximum power tracking for serving as a single DC power source input to the inverter system downstream with controllers, emergency or auxiliary loads, and alternative current feedback control systems.

Abstract: A ripple current mode power converter comprised of a magnetic energy storage element, and a method of determining magnetic storage element charge duration based on periodic magnetic storage element current samples. In the preferred embodiment a controller processes a magnetic storage element ripple current, and average sampled current, to achieve high power factor forgoing the need to sense the AC signal current and voltage levels. The controller element periodically calculates the magnetic storage element charge duration to control the state of the switch element to maintain the AC input current proportional to the AC input voltage.

Abstract: A switching power source apparatus can reduce the size of a transformer and realize the zero-voltage switching of a switch. The apparatus is compact, highly efficient, and low in noise. The apparatus has a series circuit connected to each end of a DC power source (Vdc1) and including a primary winding (5a) of a transformer (T) and a main switch (Q1), a rectifying-smoothing circuit to rectify and smooth a voltage that is output from a secondary winding (5b) when the main switch (Q1) is turned on, a series circuit connected to each end of the primary winding (5a) and including an auxiliary switch (Q2) and a clamp capacitor (C1), a series circuit connected to each end of the primary winding (5a) and including an auxiliary reactor (Lx), a diode (Dx1), and a snubber capacitor (Cx), a series circuit connected to each end of the auxiliary switch (Q2) and including a diode (Dx2) and the snubber capacitor (Cx), and a control circuit (10) to alternately turn on/off the main switch (Q1) and auxiliary switch (Q2).

Abstract: A multi-output DC-DC converter that can optimize its cross-regulation performance is proposed, in which a nonlinear inductive element functioning as a leakage inductance of an output coupled inductor is placed on the output channel of at least one secondary circuit coupled to a secondary winding of a transformer. The inductance of the nonlinear inductive element is varied in inverse proportion with the variation of the current flowing through the nonlinear inductive element. When the load on an output end of the DC-DC converter is changed, the output channel having a higher load current is configured to produce a lower leakage inductance and the output channel having a lower load current is configured to produce a higher leakage inductance, and thereby balance the output currents flowing through the output channels of the DC-DC converter.

Abstract: A digital PID controller for controlling the operation of a switching power converter is disclosed. A data converter is provided for converting the analog sense voltage to a digital sense voltage. A difference circuit then determines the difference between the digital sense voltage and a reference voltage as a digital error voltage, which reference voltage represents a desired output DC voltage for the power converter. A digital compensator processes the digital error voltage. The digital compensator includes a PID compensation network for compensating the digital error signal with a discrete time PID control law and a postprocessing filter for processing the output of the PID compensation network, comprised of a sinc filter with variable parameters to define the operating characteristics thereof, such that a first notch associated therewith can be placed at a desired frequency.

Abstract: A DC-DC converter is provided which includes a switching element, a choke coil, a flywheel diode, an output capacitor, a diode, and an auxiliary transformer having primary and secondary windings. The primary winding and the switching element constitute a first series circuit such that one terminal of the primary winding is connected to the drain terminal of the switching element, and the secondary winding and the diode constitute a second series circuit such that one terminal of the secondary winding is connected to the cathode terminal of the diode, where the other terminal of the second winding is connected to the positive terminal of a DC power source, and the anode terminal of the diode is connected to the negative terminal of the DC power source.

Abstract: There is disclosed a current balancing circuit for use in a switching power supply unit that operates in parallel with one or more other switching power supply units with current balancing terminals connected to each other. The current balancing circuit comprises a first resistor that receives a detection signal of the output current input via a diode and outputs an output current detection voltage; a second resistor connected between the current balancing terminal and a connection point between the first resistor and the diode; an operational amplifier that outputs a signal corresponding to the different between the output current detection voltages; and a switching circuit.

Abstract: The present invention relates to a multi-period cycle-alternative switching mode power supply control device and its control method, and the device comprises: a power transfer control unit, a dimming bias control, a burst timing control, and a steering logic; and the method is a power control method that uses a burst timing control to produce an ON_OFF (High_Low) control timing, and after regulated power with a different amplitude is added to the OFF period of the burst period between two ON_OFF periods, two or more mixed periods are used to regulate the timing to a highly reliable and a broad dynamic range. The device of the invention can effectively control certain power transfer components of specific nature and assure that those components and the loading at the rear end can operate more efficiently in a reliable range of a specific nature.

Abstract: A DC converter has a main switch connected in series to a primary winding of a transformer, and a series circuit of a capacitor and an auxiliary switch that is connected to both ends of the primary winding of the transformer or to both ends of the main switch, and also rectifies and smoothes a voltage of a secondary winding of the transformer to provide a DC output by alternate ON/OFF operations of the main switch and the auxiliary switch. This DC converter includes an error detector that detects an error by comparing the DC output to a reference voltage, a control circuit that controls ON/OFF of the main switch and the auxiliary switch based on the error detected by the error detector, and an activator that activates the control circuit by supplying, as power, an output of a joint of the auxiliary switch and a capacitor to the control circuit.

Abstract: An error detection circuit includes: a Zener diode having a cathode connected through a resistor to a second DC output with a higher voltage than that of a first DC output; a voltage divider circuit; and a PNP transistor having an emitter connected to the first DC output, and a base supplied with an output voltage of the voltage divider circuit. A Zener voltage of the Zener diode and a voltage dividing ratio of the voltage divider circuit are set so that the output voltage of the voltage divider circuit is equal to a value obtained by subtracting the base-emitter voltage of the PNP transistor Q1 from the voltage of the first DC output, and that temperature characteristic of the output voltage of the voltage divider circuit is set at a value canceling temperature characteristic of the PNP transistor.

Abstract: An inverter for use in connecting a DC power source to the utility grid includes a single DC-DC conversion stage, maximum (source) power tracking, and current control based on feed-forward compensation as a function of an input power commanding voltage, rectified utility line voltage, and either a scaled and squared inverse or a scaled inverse of RMS utility line voltage.

Abstract: A power source supplies an input voltage. A voltage conversion circuit converts the input voltage from the power source into an operating voltage to be used to drive an electric load. A detection circuit measures an insulation resistance value on the output side of the voltage conversion circuit. A control circuit controls a voltage conversion ratio in the voltage conversion circuit, which is expressed as a ratio of the operating voltage to the input voltage, in accordance with the insulation resistance value detected by the detection circuit. The control circuit sets the voltage conversion ratio such that the operating voltage becomes lower at the time of degradation of an insulation resistance than at the time of normal operation thereof.

Abstract: A power factor correction circuit includes; a series circuit connected to a positive-electrode output terminal P1 and negative-electrode output terminal P2 of a full-wave rectifying circuit B1, which rectifies an having current power-supply voltage of an alternating current power-supply Vac1, and including a booster winding 5a and a wind-up winding 5b wound on a booster reactor L1, a diode D1 and a smoothing capacitor C1; a series circuit, connected between the positive-electrode output terminal P1 and the negative-electrode output terminal P2 and having the booster winding 5a, a ZCS reactor L2 and a switch Q1; a diode D2 connected between a junction, between the switch Q1 and the ZCS reactor L2, and the smoothing capacitor C1; and a control circuit 10 that controllably turns the switch Q1 on and off for controlling an output voltage of the smoothing capacitor C1 to a given voltage.

Abstract: An auto-switching converter with PWM and PFM selection supplies a boosted DC power to a load through a power switch unit. A starter outputs a starting-enabling signal. An auto PWM/PFM controller is connected to the starter for outputting a selection signal. A controller and a PFM controller are connected to the auto PWM/PFM controller, the power switch unit and the load for transmitting a PWM control signal and a PFM control signal to the power switch unit, respectively, for controlling the switching action of the power switch unit.

Abstract: A method for driving a gas discharge lamp (1) is described, wherein electric first DC power is provided at a relatively high voltage and a relatively low current. Said first power is converted down to second DC power at a relatively low voltage and a relatively high current. Said second power is fed to a gas discharge lamp, preferably via a commutator. The conversion of said first power to said second power is performed in at least two steps, a first one of such steps including the step of converting down said first power to an intermediate DC power at an intermediate DC voltage lower (VM) than said first DC voltage but higher than said second DC voltage. A downconverter device (30) for use in a driving apparatus (10) for a gas discharge lamp (1) is described. The downconverter device comprises at least two downconverter units (31, 32) connected in series, for converting down said intermediate DC power to said second power.

Abstract: A power inverter control adjusts input power to track with output power to reduce energy handling requirements for an inverter DC bus. Input power to the power inverter circuit is measured and compared with a measurement of inverter output power. The comparison result is applied to a power factor correction circuit to adjust input power to track with output power, while obtaining a good power factor for the power inverter circuit. The energy requirements and ripple voltages or ripple currents on the DC bus are reduced, leading to a reduction in rating specifications for passive energy storage elements on the DC bus.

Abstract: A power converter delivers electrical power from an electrical power source to a load according to a plurality of operation modes corresponding to different levels of input voltage or output current. The power converter comprises a power stage for delivering the electrical power from the power source to the load, a switch in the power stage that electrically couples or decouples the load to the power source, and a switch controller coupled to the switch for controlling the on-times and off-times of the switch according to the plurality of operation modes. Each of the operation modes correspond to associated ranges of at least one of an input voltage to the power converter and an output current from the power converter, where the associated ranges are different for each of the operation modes.

Abstract: A power system employs an outer voltage feedback loop and an inner current feedback loop to control a power converter, such as a DC to AC inverter for transferring electrical power between a power source, for example a photovoltaic array, and a load, for example a power grid. The outer loop accommodates variations in the output of the power source, for example accommodating anomalies in IV characteristics such as IV droop characteristic associated with photovoltaic cells. The outer loop may employ a first control regime or a second control regime, for example, dependent on whether a DC bus voltage or power is smaller than a value corresponding to measurement resolution or expected noise.

Abstract: A system for use in ac to ac or dc to ac power conversion equipment to detect faults in an inverter when the inverter is in a high impedance mode. The system detects ground faults or cross wiring conditions by converting the inverter outputs to digital signals and evaluating the frequencies of the resulting signals. The system keeps the inverter in the high impedance mode until after it has been determined that neither of the described abnormal statuses exist. The system tests for both of the abnormal statuses on power up and thereafter tests only for a ground fault whenever the inverter switches are disabled.

Abstract: A method and apparatus are implemented in software to control motor speed as a function of available power in a DC source-inverter-AC motor system, i.e. to perform maximum power tracking of motor speed. An inverter or motor drive converts DC power from a DC source, such as a solar panel, to AC power, to power the motor. The inverter or motor drive is controlled by software, implemented either by programmable features built directly into the inverter or drive or by a separate programmable device connected to the inverter or drive, to track motor power as a function of source power. The software-controlled inverter or drive sets motor speed as a function of source power by sensing only a single parameter, the DC source voltage. The software-controlled inverter or drive samples the source voltage at preset intervals, and changes the frequency of the AC output of the inverter or drive to match or track the available power so that the motor operates at or near its optimum for any source voltage.