Abstract: An electronic control arrangement for controlling the power applied to an electrical load, in which the electronic control includes in its memory a predetermined power control parameter look-up table associated with each of a plurality of potentially applicable voltage ranges. Each table contains the appropriate control parameters for controlling the load when the associated one of the input voltage ranges is applied to the load. The control, in response to an input signal identifying the voltage to be applied, selects the control parameters from the look-up table associated with the identified voltage. This signal may be generated by voltage sensing circuitry which monitors the supply voltage, or by a manually adjustable circuit which enables presetting for a particular supply voltage.

Abstract: A method and apparatus for controlling a fire pump motor for use in a building having a water supply for a fire protection system, a power line, and a pressure sensor. The pressure sensor detects a high or low system water pressure with respect to a reference water pressure. A voltage controller is coupled between the power line and the fire pump motor for controlling the voltage from the power line to the fire pump motor, responsive to indications from the pressure sensor. The voltage controller increases the voltage to the fire pump motor to full voltage and runs the fire pump motor at full voltage for a minimum run time and until high pressure is indicated. The voltage controller then decreases the voltage to the fire pump motor from full voltage to a predetermined voltage level. The voltage controller holds the voltage to the fire pump at the predetermined voltage level for a first preset period of time. The voltage controller thereafter decreases the voltage to the fire pump motor from the predetermined voltage level to zero. The voltage is increased any time low pressure is indicated. The voltage is subsequently decreased from full voltage, held at the predetermined level, and decreased to zero when high pressure is indicated.

Abstract: A system and method for coordinating shunt reactance switching in a system with a transformer having a primary voltage and a secondary voltage for supplying low voltage power to a load. Voltage and power meters are provided for measuring the primary voltage and the reactive power flowing to the load. A programmable logic controller receives as one set of inputs measurements of primary voltage and reactive power flowing to the load, and as another set of inputs, predetermined ranges establishing high and low limits for the primary voltage and the reactive power. Based on these inputs, the programmable logic controller connects or disconnects at least one shunt reactance to maintain the load voltage substantially constant.

Abstract: The authors propose a method to regulate a single-phase AC source by using a series-connected auxiliary voltage source. A voltage source inverter, connected in series with the AC supply through a transformer, is used to compensate the input voltage variations in order to achieve a regulated load voltage. Input power factor improvement can also be obtained, when operating with reactive load, by phase-shifting the compensating voltage with respect to the input voltage. The total kVA rating for the system is a fraction of the load total power, and is determined by the maximum allowable line voltage variation. The use of a series connection together with a high-performance modulation technique results in a fast dynamic response and a small-size filter. A high-quality output is readily achieved. The authors describe the proposed method, implementation principles, design equations, and a design example. Simulated and experimental results confirm the concept and feasibility of the proposed system. >

Abstract: The insulation resistance values cna be determined by a comparator from a measurement voltage. The circuit arrangement has a first voltage divider, formed by the coupling resistance (R1) and the resistances (R2, R3) for producing a first measurement voltage (UM1). A second voltage divider is connected in parallel with the first voltage divider, and is formed from a series resistance (RV) and a measurement resistance (RM), for producing a second measurement voltage (UM2). The respective measurement voltages (UM1, UM2) are transmitted to an ADC of a microprocessor (ME) and from the respective measurement voltages and a reference voltage (UR) derived from a feed voltage (US), the insulation resistance values are determined by the microprocessor (ME). ADVANTAGE - Insulation defects are identified as faults in all circumstances and unreliable measurements due to very different voltage sizes are eliminated.

Abstract: A circuit arrangement for generating a high DC voltage utilizes a voltage multiplier cascade which requires two alternating, non-overlapping pulse trains which are generated by a pulse generator. For given applications, for example, contactless chip cards, the supply voltage is derived from an ac voltage induced into a coil and rectified by means of a bridge rectifier. This gives rise to a voltage drop. When the pulse generator operates utilizing the supply voltage, the amplitude of the output pulses is lower, i.e. a further voltage drop occurs. Therefore, in order to overcome this limitation, the pulse generator does not derive the pulses for feeding the cascade from the rectified operating voltage, but directly from the ac voltage. This results in a higher amplitude and a better efficiency. Another feature includes the blocking of the pulse generator so that it does not represent a load to the ac voltage.

Abstract: An ice melting system for a motor vehicle supplies a heater incorporated in a windshield with electric energy which is generated by a generator that is drivable by an engine on the motor vehicle. A voltage which is obtained by dividing an output voltage from the generator is applied as a control input voltage to a voltage regulator which controls the output voltage of the generator. When the voltage regulator is supplied with a control input voltage which is lower than when a battery on the motor vehicle is charged, the voltage regulator increases a current supplied to a field coil of the generator, thus enabling the generator to increase the output voltage thereof. Therefore, the heater is supplied with a larger amount of electric energy to melt ice on the windshield efficiently.

Abstract: The analysis and design of a direct nine-switch three-phase pulse-width modulated AC controller, capable of correcting input unbalance, are presented. A novel voltage unbalance correction method using positive and negative sequence voltage components is shown to have superior performance features. These features include output voltage balancing capability, full semiconductor utilization, simple implementation, and the direct control of the three output balanced fundamental voltage components. Selected examples are implemented by simulation and experimental prototyping to illustrate the validity and significance of the proposed unbalance correction control method. >

Abstract: A voltage monitoring apparatus for monitoring a value of a rectified AC voltage applied across a capacitive load is disclosed. The voltage has an AC component and a DC component. The apparatus monitors the value of the rectified cyclical AC voltage at a selected portion of the cycle. The voltage to be measured can either be the instantaneous value of the voltage at a predetermined time in the cycle, or the RMS value of the entire cycle. The apparatus is especially useful for monitoring a cathodic protection voltage applied to a metallic structure in contact with the ground and subject to corrosion, such as often applied to an underground pipeline. Such voltage is typically full wave rectified AC, and it is beneficial to know if the minimum voltage value of each cycle applied to the pipeline is below a predetermined value.

Abstract: Provision of a digital controller in which the controller controls the bearing coil current by means of a switching bridge that periodically reverses the applied voltage to the coil. The controller selects an applied voltage from a plurality of discrete voltage sources. When a rapid change in the load current is required, a relatively large magnitude of applied voltage is used. When a relatively constant magnitude of average load current is required, a relatively smaller value of voltage is applied.

Abstract: An apparatus and method for controlling the voltage applied to an induction motor is taught. Load sensing is incorporated by monitoring the current through the motor, and combining that signal with a signal derived from the AC line voltage and AC voltage across the motor. This composite signal is averaged, with the resulting averaged signal being utilized to control a device for modulating voltage applied to the motor such as a phase control integrated circuit device.

Abstract: In the first part of the paper, the torque capability of an inverter-fed saturated induction motor is determined. The maximum torque being available for short-time duty and the corresponding flux are calculated considering the limitations of the current and the voltage only. The flux weakening region consists of two parts which require different control strategies. At partial load the efficiency can be optimized. The results are implemented in a field oriented control which makes use of a flux and a voltage controller. With regard to the coupling of the d-axis and the q-axis existing in the machine, priority is given to the control of the d-components. The improvement of the performance being achieved by the new control strategy is verified by experimental results. >

Abstract: An apparatus and method for controlling the voltage applied to a load is taught. The method includes receiving an AC line voltage, generating an operating AC voltage from the AC line voltage and applying this operating AC voltage across the load. A measured signal which is a function of the magnitude of the operating AC voltage is generated, and then averaged to generate an average signal representative of the average value of the measured signal. The operating AC voltage is continually readjusted in response to changes in the average signal. The apparatus implementing this method includes terminal means for receiving an AC line voltage, means for generating an operating AC voltage from the AC line voltage, connector means for applying the operating AC voltage across the load, and voltage detection means for generating a measured signal which is a function of the magnitude of said operating AC voltage. Signal averaging means are provided for generating an average signal representative of the average value of the measured signal. Finally, the apparatus includes AC voltage modulation means for adjusting the operating AC voltage in response to the average signal. In the preferred embodiment of the apparatus of the present invention, the AC voltage modulation means comprises voltage reduction means for switching off the line voltage for a portion of each cycle, the length of the portion being determined by the average value of the measured signal. The voltage modulation means may comprise a phase control integrated circuit device for controlling a triac. The phase control integrated circuit device is responsive to the average signal to generate a control signal operative to control a triac to switch off transmission of the line voltage to the load for the portion of each cycle.

Abstract: An apparatus comprises digital data processing electronic circuitry based on self-timed elements. Moreover, it comprises a buffer that is connected either to the input or to the output of said circuitry. A filling degree signal from the buffer is fed back to a control input of a powering voltage controller. In this way the powering voltage is adjusted in such a way that the buffer tends not to fill and neither becomes empty.

Abstract: PURPOSE:To prevent the power amplifier from breaking down or to prevent the service life from being shortened by lowering or interrupting the transmission power of the power amplifier when a detected reflected wave level or the continuous time is higher than a prescribed value. CONSTITUTION:The load of a load terminal B is fluctuated or turned to an open state, and a reflection level voltage v2 detected by a detector 5 is increased. When the voltage v2 is higher than a reference voltage vr2, a voltage comparator 6 outputs an ON signal 1. A time measurement controller 8 receiving this signal measures over reflection level continuing time inputting the signal 1. When the measured time is longer than prescribed time, the controller 8 outputs a power down signal ST to a reference voltage controller 9. The voltage controller 9 receiving the signal ST switches a reference voltage switcher 10 to a terminal (b) and outputs a reference control voltage vC0 to the terminal (b) of the switcher 10 so as to lower or interrupt the transmission power of the power amplifier 1. As the result, the power amplifier 1 is controlled by the output of a voltage controller 11, and the transmission power is reduced or interrupted.

Abstract: An effective current controller algorithm is presented which achieves the elimination of voltage stress on the devices and complies with the pulse polarity consistency rule. The dynamic model of estimated electromotive force is developed to identify the fundamental line-line voltage zero crossing. This gives an optimal switching pattern of eight combinations 0-7 of states of the inverter devices. The voltage vector of the inverter output is determined from the desired voltage vector through the voltage vector selector in both EMVVC and EVVC (error voltage vector correction). As demonstrated by simulation results, the proposed EMVVC method outperforms the EVVC technique in four different data sets. >

Abstract: PURPOSE:To enable an electrostatic attraction device which sucks a board taking advantage of an electrostatic attractive force to easily separate the board by a method wherein a residual charge is restrained from occurring. CONSTITUTION:A voltage controlled in voltage value through a voltage controller 8 is applied from a direct power supply 7 to an electrode 4 of an electrostatic chuck 2 where a board 5 is attracted to an insulating member 3 which envelops the electrode 4. The voltage controller 8 is so constituted as to control the direct power supply 7, where a high voltage is applied when the board 5 is attracted to the electrostatic chuck 2 and the voltage applied to the electrode 4 is reduced to a voltage value just enough to enable the electrostatic chuck 2 to holds the board 5 by attraction.

Abstract: The vector modulation process provides a three-way side pulse pattern for controlling a current regulator supplied from a DC voltage source using semiconductor switches in a three-phase bridge circuit. In the stationary operating mode six required voltage rotors of equal magnitude are provided in each basic oscillation period, spaced apart from one another by 60 degrees electrical, each voltage vector lying in the same direction as a required voltage vector used with the two adjacent voltage vectors. The pulse times are selected so that the given required voltage vectors define the voltage mean value of the regulator output voltage. ADVANTAGE - Reduced harmonic content of regulator output and rapid dynamic regulation.

Abstract: PURPOSE:To make it possible to control in response to external environment by comparing a set voltage value after D/A conversion from a set data output of a microcomputer to a feedback voltage value in a voltage comparator, and by forming a voltage control circuit without using an interrupt circuit for the microcomputer, inputting detected information such as temperature and setting set points. CONSTITUTION:A set voltage value set by a setting portion 101 is output as a digital set point from a microcomputer 102. This set point is converted into an analog set voltage value by a D/A converter 103 and compared to an output voltage value at a voltage comparator 104, thereby generating a switching signal. A voltage controller 105 switches an input voltage from a supply power source by means of the switching signal and controls its output voltage to a predetermined voltage value by a point set by the microcomputer 102. The microcomputer 102 reads a set point from a memory and outputs it from a serial interface so that the set point can be output even another program for other purpose is being executed.

Abstract: In a converter 1 for a d.c. voltage consumer 2 supplied via a single or multi-phase a.c. voltage source 3, between the a.c. voltage source 3 and the d.c. voltage consumer 2 is arranged a rectifier 5 and an intermediate circuit 6 for controlling the voltage in the d.c. voltage consumer 2. The intermediate circuit 6 is associated with a control device 29. The control device 29 is connected at the input of the d.c. voltage consumer 2 with external voltage and/or current adjusting or monitoring devices. The output of the control device 29 is applied to a control input of a switching device 24. The switching device 24 is arranged between an electric energy store 26 and a magnetic energy store 19 and the intermediate circuit 6 is provided between the energy storage element 26 and the magnetic energy store 19. The switching device 24 may be a bipolar transistor (46, Fig 5), two devices (24, 56 Fig 6), GTO thyristors (97-99, Figs 12 and 16), IGBT (Figs 13, 14, 17 and 20). The d.c. voltage consumer 2 may be used for welding 33, 34.

Abstract: An apparatus for generating an intermediate voltage having a value between a positive voltage supply value and a negative supply value. The apparatus has low power dissipation and is dynamically stable over a range of external supply voltages. The apparatus comprises a voltage comparator having first and second input terminals and a control signal output terminal. A reference voltage generator is coupled to the positive voltage supply and generates a reference voltage which is coupled to the first input terminal of the comparator. A device having a zener characteristic is coupled to the positive voltage supply and generates a voltage which is coupled to the second input terminal of the comparator. A current source is coupled to the negative voltage supply and generates a current which is coupled to a terminal, to form the intermediate voltage, and is also coupled to the device to determine the voltage generated thereby. The voltage and the reference voltage are compared in the comparator which generates a control signal proportional to a difference therebetween which is coupled to control the current source.

Abstract: The circuit monitors an electromagnetically operated clutch, in which the electromagnet winding is connected to a switchable voltage source (2). A measuring resistor (8), across which a voltage sensor is connected, is arranged in series with the winding of the electromagnet. The voltage source is a DC voltage source on which a cyclic AC voltage (U(AC)) is superimposed whose DC voltage component (U(DC)) has two defined levels as a function of an engaging and disengaging signal.The winding is connected to the voltage source in the engaged and disengaged state of the clutch. The voltage sensor is connected to an evaluation circuit (10) for the AC voltage applied to the measuring resistor.

Abstract: A self-oscillating DC to DC voltage converter having improved efficiency. The high efficiency saturable core voltage converter 100 of the present invention provides an output voltage across an output load R L in response to the input voltage at a source node 106 of a voltage source 104. The present invention includes a transistor switching network 120, 122 coupled to the source node 106. The switching network 120, 122 generates an alternating voltage in response to oscillation of the flux within a magnetic core 116. A voltage transformer 110 then impresses an output voltage across an output load R L , thus providing a load current I L . The inventive converter 100 further includes a feedback winding 112 for providing a transistor drive current to the transistor switching network 120, 122. A portion of the transistor drive current is shunted to the source node 106 by a source feedback arrangement 126, 130.

Abstract: PURPOSE:To suppress increase of the number of parts and the loss by providing a capacitor for absorbing the flywheel current flowing through a load upon turn OFF of a main switching circuit and subjecting main switching element to negative current feedback thereby establishing constant current characteristics. CONSTITUTION:Upon turn ON of a main switching element TR1 within positive half cycle of a power supply 10, a load current flows through a diode D1, the main switching element TR1, a resistor r1 and a diode D2 into a load 12 thus charging a capacitor C1 with a polarity shown on the drawing. Upon turn OFF of the main switching element TR1, the capacitor C1 is discharged through the load 12. Since the voltage Vo of a switching signal G from a gate control circuit 30 is applied between the gate and the counter-source side of the resistor r1, voltage drop (r1.ID) across the resistor r1 due to a surge current increases upon turn ON of the main switching element TR1 and the gate-source voltage VGS of a FET decreases. Consequently, rising of the drain current ID is limited by the FET.

Abstract: PURPOSE:To suppress noise, occurring upon turn ON of an exciting coil, through a simple circuitry and to reduce provability of failure by providing a generator incorporating an exciting coil and an armature coil for generating an electromotive force corresponding to the variation of field and a semiconductor element for supplying and interrupting current to/from the exciting coil. CONSTITUTION:When the battery voltage exceeds a regulation voltage, a comparator 14 produces a Hi output signal. Consequently, output of an inverter 25 in a charge pump circuit 11 is inverted to (to) and a transistor 24 is turned OFF thus interrupting power supply to the gate. On the other hand, a transistor 34 in a gate discharge circuit 12 receives Hi output from the comparator 14 and turned ON thus blocking the current 12 of a constant current circuit 36 from being fed to a transistor 33. Furthermore, a transistor 35 is turned OFF and current 13 is fed from a constant current circuit 37 to the transistor 33. Consequently, the current 13 of the constant current circuit 37 is fed to a transistor 32 thus discharging the gate thereof. As a result, a semiconductor element 8 is turned OFF and the exciting current of an exciting coil 4 decreases thus reducing the power to be produced by a generator 3.

Abstract: The failure of the a.c. voltage is detected by digital evaluation of the frequency of the mains voltage. The a.c. voltage (U) is converted into half-waves and fed to a retriggerable monoflop circuit (18) whose time constant is slightly greater than the period of the a.c. mains voltage. The a.c. voltage is transformed or potential divided to match it to the circuit (14) for detection of the voltage failure. The frequency of the mains voltage can be increased and the monoflop's time constant corresp. reduced. USE/ADVANTAGE - Simple and reliable long-term detection of a.c voltage failure.

Abstract: PURPOSE:To realize a system voltage controlling method and device which can make the stable supply and quality improvement of electric power and improve the reliability and service life of facilities. CONSTITUTION:A fuzzy inferring means (3000) is provided to a system voltage controller and a control coefficient for making and discriminating voltage controlling computation is obtained by performing correction (4000) based on the results of fuzzy inference. Even under such a condition that the voltage pattern varies due to the variation of the load, not only an aimed voltage can be maintained with high accuracy, but also the number of tap switching times can be sharply reduced.

Abstract: The authors describe a technique for removing voltage harmonic distortion encountered in uninterruptible power supplies (UPSs) and active power line conditioners by variable voltage gain, with potential applications also in active filter design and arbitrary waveform synthesizers. They have adapted voltage amplitude modulation (double sideband, large carrier) for performing harmonic cancellation of power signals. They then validate the concept for power signals using a dynamic MOSFET tap switching autotransformer regulator under load for sinusoidal reconstruction and regulation. Alternative closed-loop AC switching regulator implementations are also mentioned. >

Abstract: PURPOSE:To dispense with a resistor for current detection and prevent the waste of power for detection of lock condition by detecting whether or not counterelectromotive voltage by rotation while the driving current to a motor is interrupted. CONSTITUTION:A microcomputer 13 outputs a pulse drive voltage Vd from an output port 13a to turn on a field effect transistor 2 and a drive a motor 1. The microcomputer 13 detects the voltage VD across a motor through a voltage controller 11 and an AND gate 12. When the current application to the motor 1 is broken, the terminal voltage of the motor 1 becomes lower than the application voltage by the amount of electromotive force. The microcomputer 13 detects the terminal voltage VD of the motor 1, after the current application to the motor is interrupted, so as to judge the lock condition of the motor 1. The abnormal heating, etc., of the motor 1 can be prevented.