Abstract: A new three-phase unity power factor rectifier with a three-switch buck-derived input stage and a DC/DC boost converter output stage is presented. This system has a wide input voltage range and a continuous sinusoidal time behavior of the input currents lying in phase with the input voltages which is also guaranteed in case of a failure in one phase of the mains. The input currents are controlled using a switching state sequence showing minimum switching losses. A multi-loop system control is realized by an outer output voltage controller and an inner-loop buck+boost inductor current controller. Furthermore active damping of the input filter resonance is provided. For increasing the output power of the system a parallel connection of two interleaved units is proposed. There, a low input current ripple is achieved, and the cut-off frequency of the input filter can be shifted to higher frequencies (resulting in improved control dynamics and a more compact design downsizing of the inductors and of the input filter).

Abstract: This paper describes the current control method and the switching scheme of a cascaded five level inverter based grid connected single phase photovoltaic system. For the current control a dual polarised ramptime zero average current error control method is applied, which provides good current regulation, and a narrow ripple current frequency band. Simulation results which demonstrate the method are presented. The redundant inverter states of the five level cascaded inverter allow for a cyclic switching scheme which minimises the switching frequency, equalises stress evenly on all switches and minimises the voltage ripple on the DC capacitors. Simulation and experimental results of a multi carrier PWM voltage controller showing the effectiveness of the switching scheme are presented.

Abstract: A core voltage for a core logic region of an integrated circuit is specified by a programmable register on the integrated circuit. Output terminals on the integrated circuit are coupled to the programmable storage location and supply voltage control signals for a voltage regulator to specify the core voltage according to the contents of the programmable register. The output terminals may output a programmable voltage setting or a fixed voltage setting that specifies a default core voltage value, depending on reset conditions.

Abstract: An energy management system for a motor vehicle has a first voltage supply terminal having a first nominal voltage and a second voltage supply terminal having a second nominal voltage. At least one of the first and second voltage supply terminals has a battery. A universal bi-directional DC-DC converter is coupled to exchange energy between the first and second voltage supply terminals. A third voltage supply terminal is provided for exchanging energy between the DC-DC converter and an external vehicle electrical system or battery charger. The energy exchanged between the first or second voltage supply terminals and the third voltage supply terminal is independent of the voltage and polarity of the external vehicle electrical system or battery charger.

Abstract: A voltage regulator with an input terminal to be coupled to an input voltage source and an output terminal to be coupled to a load. The voltage regulator has a first switch to intermittently couple the output terminal to the input terminal, a voltage sensor to detect a voltage at the output terminal, a current sensor to detect a current flowing along a circuit path between the input terminal and the output terminal, and a controller connected to the switch, the voltage sensor and the current sensor. The controller is configured to close the first switch if the voltage is less than a first threshold voltage and the current is less than a first threshold current, and the controller is configured to open the first switch if the voltage is greater than a second threshold voltage and the current is greater than a second threshold current.

Abstract: Generators typically regulate terminal voltage via automatic voltage regulator and exciter equipment. The desired high side (transmission side) voltage schedule is usually maintained by the power plant operator or by slow SCADA-type process control computers. Power system dynamic performance, however, can be improved by faster regulation of the transmission voltage. Contrasted to generators, static VAr compensators are designed specifically for transmission voltage regulation. The transmission voltage is directly regulated at high speed. Total SVC and medium voltage component reactive power ratings are referred to the transmission side. All medium voltage equipment are designed to support the transmission side reactive power and voltage regulation requirements. The droop (slope) setting is usually small compared to generators regulating terminal voltage. This paper introduces the panel session on secondary voltage control. The author outline various methods for tighter high side voltage control, with emphasis on control of hydro generation in the US Pacific Northwest.

Abstract: A system and method for biasing supply voltage requirements that are input to a voltage regulator to facilitate testing a computer system with supply voltages above and below specified operating values. The present invention may also be used to compensate a voltage regulator that is not outputting the supply voltage required by the computer system. The system includes a processor voltage signal indicative of supply voltage required by one or more components in a computer system during operation, at least one other voltage signal indicative of margined or biased supply voltage for the computer system, and a selection control signal for selecting between the processor voltage signal and the at least one other voltage signal. The processor voltage signal, the at least one other voltage signal, and the selection control signal, are input to a multiplexer. The multiplexer outputs a voltage identification signal to the voltage regulator based on the processor voltage signal, the at least one other voltage signal, and the selection control signal.

Abstract: A high efficiency switching controller for use in a switching power supply (SPS) includes a current control device coupled to a voltage source of the SPS and a switch connected between the current control device and an output voltage circuit of the SPS. An under voltage lockout regulator coupled to the output voltage circuit of the SPS and the switch controls the state of the switch based on a voltage of the output voltage circuit and a bias unit coupled to the under voltage lockout regulator provides current to circuitry within the switching controller based on the voltage of the output voltage circuit. A protector within the high efficiency switching controller provides a control signal to the pulse width modulator unit to control the gate drive signal in response to an operating condition of the switching controller. Additionally, the control signal can periodically enable the pulse width modulator unit in response to a voltage of the output voltage circuit so that the gate drive signal includes groups of gate drive pulses.

Abstract: Described is a circuit arrangement of a control device for monitoring a voltage with regard to voltage deviations above a specific voltage value, and for outputting a reset signal for interlocking of output elements that are controlled by the control device if a voltage deviation above the voltage value arises. The arrangement includes an arrangement for generating a reference voltage, a first comparator for comparing the reference voltage with a first comparison voltage value, which is derived from the voltage to be monitored multiplied by a first proportionality factor, and for outputting the reset signal, and a second comparator. To ensure that the circuit arrangement can monitor the voltage to be monitored with regard to whether it exceeds or is below two independent and freely definable comparison voltage values, it is proposed that the second comparator compare the reference voltage with a second comparison voltage value which is derived from the voltage to be monitored multiplied by a second proportionality factor, and it is proposed that the second comparator output the reset signal.

Abstract: The paper describes topology and control of three-phase DC-to-AC converter for variable speed cage induction machine. The proposed DC-to-AC four-quadrant converter provides wide range frequency and amplitude sinusoidal voltage. The sinusoidal voltage is produces by PWM modulation passive LC filter and control system. The multiloop controller consists of voltage controller and a current controller. Experimental results have been given to verify the proposed topology and the control scheme. The results confirm the practical feasibility of the topology and control system.

Abstract: This paper presents a soft-switching mode rectifier (SSMR) consisting of a power factor correction zero-voltage-transition-pulse-width-modulated (PFC ZVT-PWM) converter and a high-frequency transformer-coupled DC/DC zero voltage switching clamped voltage (ZVS-CV) converter. An easily implemented ZVT soft-switching mechanism is developed to reduce the switching losses and stresses of the power switches in the PFC ZVT-PWM converter. The operations of the proposed SSMR in various modes are analyzed in detail and the associated governed equations are derived. Then accordingly, a quantitative design procedure is developed to find the values of soft-switching circuit components. In the control aspect, the dynamic model of the SSMR is derived and a current waveform controller is designed, such that sinusoidal line current with low harmonics and near unity power factor is obtained. Under this condition, a voltage controller is also designed for yielding good DC output voltage control characteristics. Validity of the designed SSMR is verified experimentally.

Abstract: In this paper, a proposed system comprising of a series active filter and passive branches tuned at some characteristic harmonics is introduced. The system is capable of compensating current and voltage harmonics, three-phase voltage unbalance, reactive power and voltage sags and swells in distribution networks supplying nonlinear loads. It combines the features of both the universal power quality conditioner and the dynamic voltage restorer. The series active filter is current-controlled to force the drawn current to be sinusoidal in phase with the mains voltage. A fuzzy logic-based controller is adopted to adjust the reference signal for the system. Thus, the source current and voltage waveforms are almost sinusoidal and in phase. Meanwhile, load voltage magnitude is fixed under a wide range of faulty and healthy operating conditions. Moreover, the compensation capacity of the proposed system is compared to the conventionally-controlled series active filter. The integrity and efficacy of the system are verified through simulation results.

Abstract: Piezoelectric transformers (PZT) can be used advantageously in high output voltage DC-DC converters. In such applications, the output section includes a voltage doubling rectification scheme to help increase the output voltage. This topology was modeled and analyzed by considering the expected voltage and current waveforms under first harmonics approximation. The results were then used to build a linear AC equivalent circuit that emulates the AC-DC stage. The proposed model was verified against experimental results.

Abstract: In this paper a single-switch voltage regulator is presented. The converter processes the power less than once, resulting in an efficient design. Although the current is not sinusoidal, the proposed converter complies with the Standard IEC 1000-3-2 about low frequency harmonics for a medium power stage. Additionally a fast regulation at the output voltage is obtained due to the fact that sliding mode control is used. Analysis, simulation and experimental results of the converter are presented.

Abstract: A vehicle electrical system for supplying a first load with a first direct current voltage and for supplying a second load with a second direct current voltage lower than the first direct current voltage is disclosed. The vehicle electrical system includes: a multiphase alternating current generator having star-connected armature windings with respective phase winding terminations and a common center connection point wherein the generator generates a first higher alternating current voltage output at the respective phase winding terminations and a second lower alternating current voltage output at the common center connection point; a first rectifier unit electrically connected between the respective phase winding terminations and a first energy storage device and a first load for full-wave rectifying the first alternating current voltage output to be supplied to the first energy storage device and the first load; a second rectifier unit electrically connected in a circuit path between the common center connection point and a second energy storage device and a second load for rectifying the second alternating current voltage output to be supplied to the second energy storage device and the second load; and a controller electrically connected to the second rectifier unit, the second energy storage device and the common center connection point, the controller being operable to sense a voltage output level of the second alternating current voltage output and to selectively enable and disable the second rectifier unit to allow or block current flow through the circuit path between the common center connection point and the second energy storage device and the second load in response to the sensed voltage output level.

Abstract: PROBLEM TO BE SOLVED: To obtain a voltage detection circuit which conducts failure diagnosis of a differential amplification unit in response to the voltage detected by the differential amplification unit SOLUTION: When failure diagnosis is conducted, a cell controller C/C1 turns cell voltage detection switches SWa1 to SWa8 off and a cell reference voltage source switch SWc and volume adjustment circuit switches SWb1 to SWb8 on When the voltage detected by the differential amplifier units D1 to D8 differs more than 015 V from 360 V, it is determined that the differential amplifier units are in failure The result of the decision as well as the voltage value detected by the differential amplifier units are sent from the cell controller C/C1 to a battery controller B/C The battery controller B/C determines a failure based on the result of the decision and the voltage value When the cell voltage is detected, the cell controller C/C1 turns on the cell voltage detection switches SWa1 to SWa8 and turns off the cell reference voltage source switch SWc as well as the volume adjustment circuit switches SWb1 to SWb8 Each of the differential amplifier units D1 to D8 detects the voltage of the cells C1 to C8 COPYRIGHT: (C)2002,JPO

Abstract: A controller for controlling a reactive series compensator serially inserted at compensator terminals into a power transmission line for controlling the line current. The controller includes a current control loop and a voltage control loop. A current controller outputs a control voltage (ccout) indicating a desired compensator terminal output voltage (uc). A control method selector means generates, in a low output voltage region, a constant reference voltage (uDC ref) for the voltage control loop and a variable modulation index mq of a modulation signal m=md cos (ωt) −mq sin (ωt). In a high output voltage range, the control method selector outputs a constant modulation index mq and a variable reference voltage (uDC ref). The voltage controller outputs the modulation index md of the modulation signal m. Furthermore, the control method selector can include a rate limiter for limiting the change rate of the reference voltage (uDC ref). In connection with the control method selection and/or the rate limiter, a decoupling control for making the voltage and current control loops independent from each other can be used. The controllers find particular application in transformerless reactive series compensators for single-phase or three-phase control.

Abstract: A memory system has the capability to adjust a program or erase voltage if the time to program or erase is excessive. The memory system comprises at least a memory cell, a voltage value storage device, a voltage source, and a voltage adjustment circuit. The voltage value storage device stores a voltage value. The voltage source receives and converts the voltage value into a voltage. The voltage source applies the voltage to at least one memory cell. The voltage adjustment circuit is also coupled to receive the stored voltage value. The voltage adjustment circuit determines the time required to program or erase at least one memory cell using the voltage value. If the time to program or erase at least one memory cell is excessive, the voltage adjustment circuit increments the voltage value stored in the voltage value storage device.

Abstract: An adapter used in conjunction with voltage modules to provide multiple and variable DC output voltages. The adapter may include a circuit for stepping down an AC input voltage to lower AC output voltages. A voltage module is provided having an interface bus, configured to be coupleable to a distribution bus on the voltage adapter. Preferably, the voltage module includes AC-DC conversion circuitry, such that the AC output voltages received from the adapter may be converted to DC voltages. Once the adapter and voltage module are coupled together, the voltage module allows the user to select among the multiple DC output voltages provided. In some embodiments, the adapter includes additional circuitry for converting the stepped-down AC voltages into DC output voltages. Additional separate voltage modules may be coupled to the first voltage module, in series, to form a modular stack of voltage modules. Like the first voltage module, the second voltage module may have a selectable output voltage, as well.

Abstract: A direct duty cycle current sharing controller (42) and a method for controlling the output current of parallel coupled voltage regulator. A current sense amplifier (58) is provided to amplify the output voltage of a current sensor of a voltage regulator. A share bus amplifier (64) is provided to drive the share bus (SHARE) to a voltage representing the highest voltage regulator current of parallel coupled voltage regulators. A share adjust amplifier (68) provides the error voltage directly to the control terminal of a pulse width modulated (PWM) comparator (52). The share adjust amplifier overrides any feedback voltage currently being provided by the PWM controller and takes direct control over the duty cycle of the drive signal. Direct duty cycle current share control is provided under all modes of operation, even during modes where the voltage regulator is operating out of regulation, such as during soft start.

Abstract: A voltage control circuit that programs or erases memory cells comprises an internal voltage value store, a register device selectively coupled to an external voltage value source or the internal voltage value store to receive a voltage value, a voltage output circuit coupled to the register device to receive the voltage value and to output a corresponding voltage to the memory cells, and a verify circuit determining the time to successfully program or erase the memory cells. The register device allows the memory cells to be programmed or erased with voltage values designated by the external voltage value source to determine programming and erasing characteristics of the memory cells. Voltage values producing acceptable programming and erasing characteristics are saved in the internal voltage value store.

Abstract: A precision wide-range variable delay system whose delay is independent of process, voltage, and temperature variations. A delay controller supplies a voltage, that is independent of process, voltage, and temperature variations, and that is used in a delay line to set the amount of delay through all individual delay elements cascaded together inside of the delay line. The number of cascaded delay elements determines the maximum delay of the delay system. An output voltage controller regulates the output voltage swing of the output from the delay system for stability of the delay over voltage variations. The desired delay from the system is variable and is determined by the user. The pre-delay timing relationships of multiple signals, that are delayed, is maintained by the delay system.

Abstract: An AC induction motor is controlled by dynamically matching energy use by the motor to the load on the motor. First and second SCRs are connected in parallel with each other in opposing polarities for each phase of the applied AC voltage. A trigger generator couples trigger control signals to the respective gates of the SCRs responsive to the timing of sensed zero-crossing events of the AC voltage and current in the respective phase applied to the motor winding. The first and second SCRs are alternately triggered into a conductive state during each alternation of the applied AC voltage and are alternately inhibited from the conductive state for an interval in time proportional to a measured difference in time between the AC voltage zero-crossing and the corresponding AC current zero-crossing as determined by comparing the time difference between successive first and second interrupts corresponding to the zero-crossing events with a continuously running time base.

Abstract: This paper presents results of voltage transient tests. The primary aim of these tests is to develop an experimental understanding of what happens after a voltage transient arrives at the stator winding of an electrical machine. The test was performed on the stator of a 6 kV induction motor. The present measurements are performed with a 42 V input voltage step transient. The results show that, among the stator coils, the highest voltage peak appears across the coil next to the input; thus, this first terminal-end coil is subjected to the highest voltage stress. It was found, additionally, that the surge voltage distribution within the first coil is independent of the terminating condition at the neutral end of the winding, i.e. either grounded or ungrounded. The direct measurement shows that the inter-turn voltage is non-linearly distributed and the amplitude of the inter-turn voltage of the first coil depends quite considerably on the features (e.g. length) of the cable feeding the winding. The present experimental findings should be of help to those concerned with the turn insulation in motors fed by a frequency converter and surge protection problems of large AC motors.

Abstract: An excitation controller includes a reactive current detector for detecting a reactive current output from a synchronous machine connected, by way of a tap-changer-equipped transformer including a tap changer for changing taps of the transformer under load conditions, to a transmission system, a tap controller for setting a tap ratio of the tap-changer-equipped transformer according to an output terminal voltage of the synchronous machine, and a voltage setter for setting a reference voltage for an output voltage of the synchronous machine based on a second reference voltage of the tap-changer-equipped transformer at a side connected to the transmission system, the tap ratio set by the tap controller, and the reactive current detected by the reactive current detector. The excitation controller further includes a control unit for controlling an excitation system for exciting the synchronous machine according to the first reference voltage set by the voltage setter.

Abstract: A new method of voltage regulation of the constant frequency (CF) zero voltage switching (ZVS) quasi-resonant converter (QRC) based DC-DC switched mode power supply is presented. The output voltage of the half wave (HW) CF-QRC varies, when the load and the input voltage changes. To maintain constant output voltage, a closed loop system with a PI controller is proposed. The present work deals with the design and implementation of CF-ZVS-QRC operating in the HW mode. A high-speed micro-controller is used for the realization of PI controller and for the generation of trigger pulses for the switches. The experimental results are compared with theoretical results and they closely agree with each other.

Abstract: A voltage regulation steering circuit reads a voltage input code from a device and detects a set of predetermined conditions for gradually counting an output voltage code. Depending upon the set of predetermined conditions, the steering circuit either gradually counts the output voltage code from a predetermined initial voltage code to the voltage input code or gradually counts the output voltage code from the voltage input code to a predetermined low voltage code. As the steering circuit gradually counts from the predetermined initial voltage code, the steering circuit compares the output voltage code to voltage input code until the output voltage code matches the voltage input code. As the steering circuit gradually counts from the voltage input code, the steering circuit compares the output voltage code to the predetermined low voltage code until the voltage output code matches the predetermined low voltage code. The output voltage code is provided from the steering circuit to a voltage controller.