Abstract: A column analog-to-digital converter having a voltage comparator and a counter is arranged for each a vertical signal line. The voltage comparator compares a pixel signal inputted via the vertical signal line at each row control signal line with a reference voltage, thereby generating a pulse signal having a length in time axis corresponding to the magnitude of a reset component and a signal component. The counter counts a clock to measure the width of the pulse signal until the end of the comparison operation of the comparator, and stores a count at the end of the comparison. A communication and timing controller controls the voltage comparator and the counter so that, in a first process, the voltage comparator performs a comparison operation on a reset component with the counter performing a down-counting operation, and so that, in a second process, the voltage controller performs the comparison operation on a signal component with the counter performing an up-counting operation.

Abstract: An apparatus and method of wirelessly sharing power by an inductive method are provided. The apparatus includes a first battery supplying power; a rectifier supplied with an AC voltage, converts the AC voltage into a DC voltage, and outputs the DC voltage; an inverter supplied with the DC voltage, converts the DC voltage into the AC voltage, and outputs the AC voltage; a power control/conversion unit connected to the rectifier or the inverter and supplying power to charge the first battery or a second battery that is provided in an external device as a power supply for the first battery; and a communication unit communicating with the external device.

Abstract: This paper presents the modeling, controller design and a steady-state analysis algorithm for a wind-driven induction generator system. An output feedback linear quadratic controller is designed for the static synchronous compensator (STATCOM) and the variable blade pitch in a wind energy conversion system (WECS) in order to reach the voltage and mechanical power control under both grid-connection and islanding conditions. A two-reference-frame model is proposed to decouple the STATCOM real and reactive power control loops for the output feedback controller. To ensure zero steady-state voltage errors for the output feedback controller, the integrals of load bus voltage deviation and dc-capacitor voltage deviation are employed as the additional state variables. Pole-placement technique is used to determine a proper weighting matrix for the linear quadratic controller such that satisfactory damping characteristics can be achieved for the closed-loop system. Effects of various system disturbances on the dynamic performance have been simulated, and the results reveal that the proposed controller is effective in regulating the load voltage and stabilizing the generator rotating speed for the WECS either connected with or disconnected from the power grid. In addition, proper steady-state operating points for an isolated induction generator can be determined by the proposed steady-state analysis algorithm. Constant output frequency control using the derived steady-state characteristics of the isolated induction generator is then demonstrated in this paper

Abstract: The present invention discloses a primary-side feedback switching power supply that uses a sample-and-hold circuit to obtain a corner voltage of a harmonic wave voltage while the primary-side auxiliary winding is operating at a discontinuous mode as a feedback control, and provides both voltage regulation and current limit functions. A stable voltage output is provided within the nominal input voltage and nominal output load, such that when the output reaches a current limit, the output voltage drops but the output current is controlled to remain unchanged, so as to provide an over-current protection.

Abstract: A disk drive includes a disk comprising a plurality of zones, a clock for generating a timing signal having a timing frequency, a voltage controller for providing a supply voltage, and circuitry coupled to the supply voltage and responsive to the timing frequency. Power may be conserved by receiving a host command; selecting one of the plurality of zones based on the host command; and adjusting the timing frequency and the supply voltage provided to the circuitry based at least in part on the selected zone.

Abstract: PROBLEM TO BE SOLVED: To provide a semiconductor memory device capable of saving power consumption by reducing a power supply voltage to be output to a word line driver in a standby state and a loss caused by a current leakage. SOLUTION: This semiconductor memory device 100 is constructed in such a manner that a booster circuit 20 generates a predetermined power supply voltage Vpp exceeding an external power supply voltage Vcc, and supplies it to a plurality of storage blocks B1 to Bm via a global power line GPL. Each storage block (e.g., B1) includes a local power line LPL1, a plurality of functional circuits WD11 to WD1n connected to the local power line LPL1, and a voltage controller SC1 connected between the global power line GPL and the local power line LPL1. The voltage controller SC1 outputs the predetermined power supply voltage Vpp or a first voltage Vpp-Vt in a first period and a second period respectively via the local power line PL1 to the functional circuits WD11 to WD1n on the basis of a selection signal/BS1. The first voltage Vpp-Vt exceeds the external power supply voltage Vcc, but it is lower than the prescribed power supply voltage Vpp. COPYRIGHT: (C)2006,JPO&NCIPI

Abstract: This paper discusses the dynamic performance of a distribution static compensator (DSTATCOM) coupled with an energy storage system (ESS) for improving the power quality of distribution systems. The presented integrated DSTATCOM/ESS compensator is analyzed as a voltage controller, a power factor controller and an active power controller. Modeling and control approaches are proposed, including a detailed modeling of the DSTATCOM/ESS. The multi-level control technique proposed is based on the instantaneous power theory on the synchronous rotating dq reference frame. Validation of models and control schemes is carried out through simulations by using SimPower-Systems of MATLAB. The results obtained demonstrate the good performance of the multilevel controller as well as the benefits of its use in the distribution level power quality (PQ).

Abstract: This paper presents a comprehensive model of the Back-to-Back (BtB) HVDC system based on the three-level Neutral-Point Diode Clamped (NPC) converter. Based on the developed model, a systematic design procedure for i) the ac-side controllers, ii) the voltage balancer of the dc-side capacitors, and iii) the net dc-bus voltage controller, are presented. The model is developed based on the generalized state-space averaging method and the principle of power balance. The developed model precisely describes the system dynamics if the ac grids are strongly or moderately stiff, and offers acceptable precision otherwise. The averaged nature of the model inherently renders itself for analysis in the SIMULINK/MATLAB environment, and thus provides a computationally efficient tool for the design and the performance evaluation of the control. The accuracy of the developed model and the controls are validated by comparing the results from MATLAB/SIMULINK with those obtained from the exact switching model of the system, based on digital time-domain simulation studies, using the PSCAD/EMTDC software package.

Abstract: This paper analyzes the robust stability of a voltage and current control solution for a stand-alone distributed generation (DG) unit using the structured singular value or /spl mu/-framework-based method. The voltage and current control solution consists of a discrete-time sliding mode current controller and a perfect robust servomechanism problem voltage controller, which has been shown effective in transient response and harmonic minimization in previous study without considering parametric uncertainty. The stability robustness of the system and its transient performance are investigated under various tuning parameters of the controller. The analysis results presented in this paper demonstrate that the controller parameters can be tuned and verified to satisfy a certain transient performance requirement and at the same time guarantee robust stability under system parameter uncertainties and load variations.

Abstract: A lower-cost and more precise control methodology of regulating the output voltage of a flyback converter from the primary side is provided, which works accurately in either continuous voltage mode (CCM) and discontinuous mode (DCM), and can be applied to most small, medium and high power applications such cell phone chargers, power management in desktop computers and networking equipment, and, generally, to a wide spectrum of power management applications. Two highly integrated semiconductor chips based on this control methodology are also described that require very few components to build a constant voltage flyback converter.

Abstract: An adaptive pulse positioning system for a voltage converter providing an output voltage, the system including a PWM generation circuit, a sensor, and a pulse positioning circuit. The PWM generation circuit generates a PWM signal with PWM pulses for controlling the output voltage of the voltage controller. The sensor senses an output load condition of the voltage converter and provides a load signal indicative thereof. The pulse positioning circuit adaptively positions the PWM pulses based on the load signal. A method of adaptively positioning PWM pulses that are used to control an output voltage of a voltage regulator including generating a series of PWM pulses based on a clock signal, sensing an output load condition, and adaptively shifting the series of PWM pulses based on the output load condition.

Abstract: The Dynamic Voltage Restorer (DVR) is a commercially available, popular device to eliminate voltage sags and swells in the distribution lines. Its basic function is to inject the voltage difference (difference between the pre-sag and sag voltage) to the power line and maintains the pre-sag voltage condition in the load side. Different control strategies are available depending on the compensation technique used for compensation. A new control strategy for the single-phase voltage sags based on in-phase compensation technique is described in this paper. In the designed control, the DVR initially tracks the phase angle of the supply voltage and produce a reference voltage signal with the rated load voltage magnitude. If any phase jump occurred at the supply voltage, phase angle of the reference voltage signal is adjusted slowly to track the phase angle of the supply voltage. The difference between the reference and measured voltage is injected by the DVR. Therefore with this DVR control technique, the load will not experience any phase jump or dip. The simulation was carried out using EMTDC/PSCAD software and the results show a very good level of compensation for different voltage sags.

Abstract: This article describes a controller for voltage and frequency control of self-excited induction generator (SEIG) supplying static/dynamic, balanced/unbalanced loads. The controller is a combination of a three-phase insulated gate bipolar transistor (IGBT) based current controlled voltage source inverter (CC-VSI) and a high frequency DC chopper, which keeps the generated voltage and frequency constant in spite of change in consumer loads. A mathematical model of the SEIG with this controller supplying different types of loads is developed for predicting the behavior of the system under transient and dynamic conditions. The simulated results show that generated frequency and voltage remain constant with change in load. The proposed controller acts as reactive power compensator, harmonic eliminator, load balancer, and frequency and voltage regulator.

Abstract: A PFM-type voltage regulator circuit converts an unregulated input voltage into a regulated output voltage using a first transistor controlled by a pulse control circuit and a second transistor controlled by a linear regulator circuit. The linear regulator circuit controls the second transistor when the regulated output voltage falls to a predetermined minimum target voltage level, thereby maintaining the regulated output voltage at the minimum target voltage level. The pulse control circuit detects the current passing through the second transistor, and in response generates a pulse signal having a predetermined duration that fully turns on the first transistor. The voltage through the first transistor is converted to an increasing inductor current that refreshes the regulated output voltage to a maximum target voltage level. When the pulse signal ends, the regulated output voltage again begins to fall toward the predetermined minimum target voltage level, and the cycle is repeated.

Abstract: The paper proposes the algorithms of ac output voltage control in the Z-source inverter while minimizing the voltage stress across the devices. A novel switching pattern in the SVPWM is used in order to boost easily the capacitor voltage by controlling a shoot through time. The possible operating region for obtaining a desired ac output voltage to dc input voltage is analyzed. The voltage stress across the switching devices can be so mush reduced at a given ac output voltage. The proposed methods are verified with the simulation studies and experiments with 32-bit DSP.

Abstract: An equivalent continuous-time state-space model for VSC-HVDC in the synchronous dq reference frame has been established in the paper. Based on the model, relevant control strategies have been developed for the cases of supplying active and passive systems. The multi-input multi-output (MIMO) control schemes are emphasized in designing power controller and voltage controller. The scheme features feed forward compensation to decouple the d- and q-axis of the voltage source converter (VSC) model, which ensures the independent control of active and reactive power, DC voltage and reactive power as well. Simulations have been performed on PSCAD/EMTDC, a visual design environment for power system studies. The validity of the mathematic model and the feasibility of the control strategies have been proved by the simulation results.

Abstract: This paper proposes a fully digital control of boost power factor preregulators (PFPs) with input voltage estimation that is suitable for smart-power integration. The proposed solution features a minimum pin count by avoiding input voltage sensing for the generation of the internal current reference and by sensing the output voltage through the direct sampling of the voltage across the power switch during its off interval at the line voltage peak. The control algorithm requires the estimation of the rectified input voltage, that is simply done by exploiting the integral part of the current loop proportional-integral regulator, and a phase-looked-loop (PLL) synchronization with the estimated line frequency for sampling the output voltage and rejecting the low-frequency output voltage ripple. The provisions needed to ensure correct output voltage sensing, even during transient and light-load conditions, are also discussed. Experimental results on a single-phase boost PFP show the properties of the proposed approach

Abstract: A DC-DC converter having conversion efficiency that is not lowered by input voltage change. A mode control circuit of the DC-DC converter monitors the input voltage, output voltage generated from the input voltage, and output current. The output current changes in accordance with the output voltage. Based on the input voltage, output voltage, and consumption current of a controller of the DC-DC converter, the mode control circuit generates a signal that is in accordance with load current in which efficiency of a switching regulator and efficiency of a linear regulator are substantially the same. The mode control circuit further compares a signal corresponding to the output current and the signal that is in accordance with the load current to generate a mode control signal. The controller operates the DC-DC converter as the switching regulator or the linear regulator in accordance with the mode control signal.

Abstract: An apparatus and method for automatically controlling voltages used to drive LED loads. A battery voltage can be boosted to a selected drive voltage level connected to current sources for driving the LED loads. The drive voltage level is selected by a controller using a headroom detect component to measure a headroom voltage across the current source. The controller adjusts the drive voltage level to maintain the headroom voltage within a predetermined operating range. The drive voltage may be used to drive a variable number of LEDs or a plurality of different LED loads connected in parallel without manual readjustment of drive voltage.

Abstract: Recently, concerns over voltage instability phenomena have been increasing, because significant voltage drops are regarded crucial in stable operations. Thus, effective voltage control schemes using voltage stability indices have been brought to attention in a considerable number of studies. The conventional voltage stability indices are mainly based on evaluating voltage stability margins to a critical point. The operator usually determines proper voltage range in power systems. In this paper we propose a voltage stability index VMPI (voltage margin proximity index) considering voltage limits, especially lower voltage limits. Simulations are run using the IEEJ West 30 machine 115 bus system

Abstract: This paper presents a DSP-based constant voltage controller for stand alone wind energy conversion system using an induction generator. The system uses a pulse-width modulated voltage source inverter (PWM-VSI) with a start-up battery. The limitation of having stand alone wind energy conversion system with self-excited induction generator (SEIG) is poor voltage regulation which occurs with change in speed and load condition. To overcome this problem, a DSP-based voltage controller is developed. It regulates the voltage when SEIG is subjected to a sudden application/removal of load. It is now possible to operate the induction generator (IG) at constant voltage from no load to full load. The amplitude of the terminal voltage of the IG is regulated by varying the modulation index of the PWM inverter. The system has an inherent current limiting feature and it requires only sensing of dc link voltage. To predict the performance of the proposed system, a MATLAB/SIMULINK-based simulation study is carried out. The control algorithm is implemented on a TMS320F243 DSP platform at the assembly language level for optimum performance of the voltage controller. Viability of the compensation process is ascertained through experimental results obtained from the laboratory prototype.

Abstract: The paper proposes a multilevel single-phase rectifier-inverter with the cascaded connection of two three-arm converters. A semisinusoidal PWM switching technique is developed to form a five-level switching pattern on the rectifier side and the inverter side simultaneously. The DC-link voltages of two converters are regulated with one voltage controller. Balance of two DC-link voltages is controlled with a feed-forward adjustment of the PWM control signal. Multiple-loop controller design of the system is presented. The feed-forward-plus-feedback control technique is employed for regulating both the rectifier current and the inverter voltage. A 2 kVA/220 V/60 Hz prototype system is set up and its control circuit is realised based on Matlab real-time control. Effectiveness of the proposed circuits is confirmed with some experimental results

Abstract: A system, method and apparatus for contact-less charging of battery operated devices is presented. There is a host charger with a power converter and resonant tank circuit and a portable device where the battery is located, with a battery charging control IC. The method obviates the need for a voltage controller in each of both the host and the portable stages, thus decreasing complexity and increasing efficiency. The charging of the battery in the portable device is controlled by a charging controller therein, which is in continual electric communication with the host, whose output power the control IC dynamically monitors and controls. Two embodiments for the charging circuitry in the portable device are presented. In one embodiment component count is minimized but battery charging is not optimized when the battery voltage is very low. In the other embodiment charging efficiency is maximized regardless of the output voltage of the battery, but additional components are utilized.

Abstract: A plurality of pickup coils 2A and 2B are provided, resonance capacitors 3A and 3B forming resonance circuits 4A and 4B resonating at the frequency of an inductive path 1 are respectively connected in series with the pickup coils 2A and 2B, and the resonance circuits 4A and 4B are connected in series. Further, the resonance circuits 4A and 4B are respectively provided with rectifier circuits 6A and 6B for rectifying voltages generated by the resonance circuits 4A and 4B. The rectifier circuits 6A and 6B are connected in parallel and feed power to a load 10. Moreover, a switch 5 is provided to switch a connected state and an open state between the resonance circuits 4A and 4B, and a voltage controller 11 is provided to control an output voltage applied to the load 10, by controlling the switch S.

Abstract: A combined digital and analogue approach is introduced to establish a dynamic Active Voltage Controller (AVC) for controlling an insulated gate bipolar transistor (IGBT), suitable for series connection of devices. In the AVC, the reference voltage dictates the switching trajectory of active voltage controlled IGBTs via a feedback loop. By means of employing adaptive and self-timing control methods to adjust the reference voltage profile according to the transient states on the power side, this new controller has achieved real-time optimization of the IGBT switching with lowest possible power losses. In particular, this new AVC has provided an efficient and flexible solution to addressing the diode reverse recovery and the IGBT-diode commutation during IGBT switch-on operation. The commonly seen voltage overshoot and extra power loss associated with diode reverse recovery voltage are greatly reduced in the new AVC. The optimal switching performance in experiments for both a single IGBT and IGBTs connected in series is given in this paper. This is an effective solution to IGBT control without snubber networks and shows the effectiveness of concurrent optimization of devices and circuits.

Abstract: A storage voltage of a battery pack is controlled with control electronics. The storage voltage of a battery pack is sensed, and a discharge mechanism is triggered if the storage voltage is within a predetermined range of voltage, to thereby adjust the storage voltage of the battery pack to below the predetermined range of voltage, or if the storage voltage is at or above a predetermined voltage, to thereby adjust the storage voltage of the battery pack to below the predetermined voltage. Control electronics sense a storage voltage of a battery pack and trigger a discharge mechanism if the storage voltage is within a predetermined range of voltage, to thereby adjust the storage voltage of the battery pack to below the predetermined range of voltage, or if the storage voltage is at or above a predetermined voltage, to thereby adjust the storage voltage of the battery pack to below the predetermined voltage. The control electronics are coupled to an electronic device and a battery pack. The control electronics are either implemented into the electronic device or the battery pack, or in a separate control electronic device.

Abstract: This paper proposes a wind energy conversion system connected to a grid using a self-excited induction generator (SEIG) based on the maximum power point tracking (MPPT) control scheme. The induction generator (IG) is controlled by the MPPT below the base speed and the maximum energy can be captured from the wind turbine. Therefore, the stator currents of the IG are optimally controlled using the indirect field orientation control (IFOC) according to the generator speed in order to maximize the generated power from the wind turbine. The SEIG feeds a (CRPWM) converter which regulates the DC-link voltage at a constant value where the speed of the IG is varied. Based on the IG d-q axes dynamic model in the synchronous reference frame at field orientation, high-performance synchronous current controllers with satisfactory performance are designed and analyzed. Utilizing these current controllers and IFOC, a fast dynamic response and low current harmonic distortion are attained. The regulated DC-link voltage feeds a grid connected CRPWM inverter. By using the virtual flux orientation control and the synchronous frame current regulators for the grid connected CRPWM inverter, a fast current response, low harmonic distortion and unity power factor are achieved. The complete system has been simulated with different wind velocities. The simulation results are presented to illustrate the effectiveness of the proposed MPPT control scheme for a wind energy system. In the simulation results, the d-q axes current controllers and DC-link voltage controller give prominent dynamic response in command tracking and load regulation characteristics.

Abstract: A flash memory device may include a memory cell array. The memory cell array may include a plurality of memory cells. The flash memory device may also include a voltage generator which generates a plurality of constant voltages. The voltage generator may comprise of a plurality of voltage regulators, wherein each voltage regulator is configured to divide a high voltage generated from a charge pump to generate at least two constant voltages having a constant voltage difference therebetween. The plurality of voltage regulators may have independent voltage dividing paths, wherein each path is configured to generate a separate constant voltage.

Abstract: To provide a control circuit of power supply unit, power supply unit and control method thereof capable of setting and adjusting a voltage value of output voltage flexibly corresponding to an instruction from outside, a voltage adjusting portion AD for adjusting first voltage setting information inputted from outside to real voltage information is provided and the voltage value of the output voltage of the power supply unit is controlled based on real voltage information outputted from the voltage adjusting portion AD. The first voltage setting information inputted from outside enables a desired output voltage to be set up by adjusting the real voltage information flexibly even if information relating to the setting of voltage set as output voltage to an external device which is a supply destination is different from actually necessary voltage value.