Showing papers on "Precision rectifier published in 1999"

Circuit and method for controlling a synchronous rectifier converter

Abstract: A rectifier having an input and an output and a method of controlling the rectifier. The rectifier comprises: (1) switching circuitry coupled between the input and the output, the switching circuitry adapted to operate in selected one of (a) an active bidirectional mode of operation and (b) an inactive unidirectional mode of operation to rectify substantially alternating current at the input to produce substantially direct current at the output and (2) control circuitry coupled between the rectifier output and a control input of the switching circuitry, the control circuitry capable of sensing an output current level of the rectifier and transitioning the switching circuitry between the active bidirectional mode and the inactive unidirectional mode as a function of the output current level thereby to prevent substantial reverse power flow through the rectifier. The rectifier is particularly useful in power systems having a plurality of rectifiers operating in parallel to prevent one rectifier from driving the other.

Status of the techniques of three-phase rectifier systems with low effects on the mains

Abstract: Based on a comprehensive study of the literature, concepts of three-phase rectifier systems with low effects on the mains are classified. Such systems are unidirectional and bidirectional self-commutated power converters with impressed output voltage or output current and line-commutated rectification in connection with passive and active filtering. Selected circuit concepts are analyzed concerning the operational behavior and the obtainable quality of the mains current. Furthermore, an evaluation of the rectifier concepts concerning utilization of the power semiconductors, rated power of the inductive and capacitive components and of the realization effort in general is given. Finally, problems of the practical application of high switching frequency PWM rectifier systems and topics of further research are discussed.

DC ripple current reduction on a single-phase PWM voltage source rectifier

Abstract: A novel topology of single-phase pulsewidth modulation (PWM) voltage-source rectifier capable of achieving not only a sinusoidal input current, but also a zero-ripple output current, is presented. The rectifier consists of a conventional single-phase PWM voltage-source rectifier, a pair of additional switches and an inductor. Hence, the proposed rectifier requires neither a large DC capacitor nor a passive L-C resonant circuit. The input current control is achieved by the conventional PWM current control technique. However, DC ripple current reduction control is difficult because one of the switching legs in the DC ripple current reduction circuit is shared with the PWM rectifier circuit. Two control methods, referred to here as the DC C inductor method and the AC inductor method, are proposed for DC ripple reduction, and the characteristics of these control methods are discussed. These control methods are implemented using a microprocessor, and the effectiveness of the circuit is confirmed experimentally. This rectifier has useful applications in uninterruptible power systems and DC power supplies, especially for cases in which the batteries are connected in parallel to the DC line.

A line-voltage-sensorless synchronous rectifier

Abstract: A line-voltage-sensorless control for three-phase pulsewidth-modulated (PWM) synchronous rectifiers is presented. A line synchronization and unity power factor control are described. Indirect synchronization without sensing the line voltage allows a standard vector-controlled inverter to be used as a synchronous rectifier without requiring any additional hardware. Furthermore, the line synchronization can be properly operated under line voltage distortion or notching and line frequency variation. All control functions are implemented with a single-chip microcontroller. It is shown via experimental results that the proposed controller gives good performance for the synchronous rectifier.

Reader for use in a radio frequency identification system and method thereof

Abstract: A contactless programmable electrostatic Radio Frequency Identification (RFID) reader that also serves as an Electronic Article Surveillance (EAS) reader is described. The RFID/EAS reader contains a detector circuit for detecting the presence of a signal carrier frequency transmitted by the transponder in response to a signal from the reader. The detector circuit has a resonator circuit which is connected to a receiver electrode. The resonator comprises a piezoelectric element with a high quality factor ‘Q’ at the resonant frequency to enhance sensitivity. The alarm carrier signal is rectified and fed to either a peak detector or an envelope detector circuit. A voltage source generates a voltage threshold to allow for operating range adjustment. A comparator compares both voltages and generates an alarm signal if the voltage signal reaches the threshold voltage. The RFID/EAS further having the capability to read the RFID contents. Alternatively, an electrostatic EAS reader (without RFID capability) having a substantially similar detector circuit is also described.

VIENNA rectifier II-a novel single-stage high-frequency isolated three-phase PWM rectifier system

Abstract: Based on an analysis of basic realization possibilities, the structure of the power circuit of a new single-stage three-phase boost-type pulsewidth modulated (PWM) rectifier system (VIENNA Rectifier II) is developed. This system has continuous sinusoidal time behavior of the input currents and high-frequency isolation of the output voltage, which is controlled in a highly dynamic manner. As compared to a conventional two-stage realization, this system has substantially lower complexity and allows the realization of several isolated output circuits with minimum effort. The basic function of the new PWM rectifier system is described based on the conduction states occurring within a pulse period. Furthermore, a straightforward space- vector-oriented method for the system control is proposed which guarantees a symmetric magnetization of the transformer. Also, it makes possible a sinusoidal control of the mains phase currents in phase with the associated phase voltages. By digital simulation, the theoretical considerations are verified and the stresses on the power semiconductors of the new converter system are determined. Finally, results of an experimental analysis of a 2.5-kW laboratory prototype of the system are given, and the direct startup and the short-circuit protection of the converter are discussed. Also, the advantages and disadvantages of the new converter system are compiled in the form of an overview.

A fuzzy-controlled active front-end rectifier with current harmonic filtering characteristics and minimum sensing variables

Abstract: A control strategy which allows conventional voltage-source current-controlled (VSCC) pulsewidth modulation (PWM) rectifiers to work simultaneously as active power filters is presented. The proposed control strategy also allows compensating the system power factor and compensating unbalanced loads. The measurement and/or calculation of the harmonics and reactive power are not required, making the proposed control scheme very simple. The active front-end rectifier acts directly on the mains line currents, forcing them to be sinusoidal and in phase with the mains voltage supply. To improve the dynamic of the system, the amplitude of the current is controlled by a fuzzy system, which adjusts the DC-link voltage of the PWM rectifier. The strategy is based on connecting all the polluting loads between the PWM rectifier and their input current sensors. The main advantages of this approach are the following: (1) there is no need to install a specially dedicated active power filter; (2) it also works simultaneously as a power factor compensator; and (3) no special and complicated calculations are required for harmonic elimination. The viability of the proposed active front-end rectifier is proved by simulation and with experimental results obtained from a 2 kVA PWM prototype.

Drive compensation circuit for synchronous rectifier and method of operating the same

Abstract: For use with a synchronous rectifier coupled to a secondary winding of a transformer and having a rectifier switch, a circuit for, and method of driving the rectifier switch and a power converter employing the circuit or the method. In one aspect of the present invention wherein the synchronous rectifier has at least first and second rectifier switches, the circuit includes: (1) a series-coupled drive winding and capacitor, coupled between a first control terminal of the first rectifier switch and a second control terminal of the second rectifier switch, that generates first and second drive signals and delivers the first and second drive signals to the first and second control terminals, respectively, and (2) first and second clamps, coupled to the first and second control terminals, respectively, that control first and second capacitive charges within the first and second rectifier switches to limit voltage excursions of the first and second drive signals.

Transcutaneous energy transmission system with full wave class e rectifier

Abstract: This inventions is a transcutaneous energy transmission system (TETS) (10) including a Class E full wave low dv/dt rectifier in the implanted receiver circuit (14). The TETS provides power for any kind of an implanted device (26) requiring a source of DC power for operation. The Class E full wave low dv/dt rectifier provides efficient conversion of radio frequency power to direct current power. Another embodiment of a TETS includes a Class E full wave low dv/dt rectifier with circuitry for synchronous rectification. A receiver circuit (34) including a Class E full wave low dv/dt rectifier configured for use with a transmitter circuit, is also disclosed.

Self-driven synchronous rectification scheme

Abstract: A self-driven synchronous rectifier circuit (42) for a power converter. The circuit comprises a transformer (49, 70) having a secondary winding with a first and second terminal, a first synchronous rectifier (14) coupled to the second transformer terminal and having a control terminal, and a second synchronous rectifier (16) coupled to the first transformer terminal and having a control terminal. The circuit (42) also comprises a first switch (44) coupled to the first synchronous rectifier (14) control terminal, and a second switch (46) coupled to the second synchronous rectifier (16) control terminal. The first (44) and second switch (46) are also coupled to the secondary winding. Switching transitions of the first (14) and second (16) synchronous rectifiers are initiated by a polarity reversal of the voltage of the secondary transformer winding.

Control of a three-phase PWM rectifier using estimated AC-side and DC-side voltages

Abstract: A new control method of a pulsewidth modulation (PWM) rectifier without measuring AC- and DC-side voltages is proposed. As information about these voltages is necessary for the controller, all required voltage values are estimated from the measured line currents and the calculated values of the input reactor voltage during switching of the rectifier circuit. The input reactor voltage can be obtained by using a differentiator that produces the derivative of the line current or by detecting the voltage induced in a secondary winding wound on the input reactor. The secondary winding creates the electric isolation between the main circuit and the controller. The proposed method is verified by experiment. This paper describes the estimation method, gives the configuration of the controller, and discusses steady-state and transient performances of the rectifier.

A planar 4.5-GHz DC-DC power converter

Abstract: In this paper, we present two DC-DC converters that operate at a microwave frequency. The first converter consists of a class-E switched-mode microwave amplifier, which performs the DC-AC conversion, and two half-wave diode rectifier outputs. The class-E MESFET amplifier has a minimum power-added efficiency of 86%, corresponding drain efficiency of 95%, and 120 mW of output power at 4.5 GHz. The diode rectifier has a maximum conversion efficiency of 98% and an overall efficiency of 83%. The second converter consists of a high-efficiency class-E oscillator and a diode rectifier. The class-E oscillator has a maximum efficiency of 57% and maximum output power of 725 mW. The DC-DC converter is planar and compact, with no magnetic components, and with a maximum overall DC-DC conversion efficiency of 64% for a DC input of 3 V, and the output voltage across a 87-/spl Omega/ load of 2.15 V.

Performance improvement of half controlled three phase PWM boost rectifier

Abstract: The potential of the half-controlled three-phase pulse-width modulated (PWM) boost rectifier is investigated based on theoretical analysis, simulations and experiments. The main advantages of this rectifier are: (1) a simpler and economical system compared to a full controlled PWM rectifier (reduced controlled switch count, single power supply for gate drives, and shoot-through free leg structure); and (2) better performance compared to a diode rectifier (actively controllable DC link voltage and lower input current total harmonic distortion (THD)). In particular, it is shown in this paper that the input current THD of this rectifier can be reduced by intentionally introducing a lagging power factor current command. Several issues for further performance improvement are pointed out for future work.

A new control scheme for single-phase PWM multilevel rectifier with power-factor correction

Abstract: A new control scheme for a single-phase bridge rectifier with three-level pulsewidth modulation is proposed to achieve high power factor and low current distortion. The main circuit consists of a diode-bridge rectifier, a boost inductor, two AC power switches, and two capacitors. According to the proposed control scheme based on a voltage comparator and hysteresis current control technique, the output capacitor voltages are balanced and the line current will follow the supply current command. The supply current command is derived from a DC-link voltage regulator and an output power estimator. The major advantage of using a three-level rectifier is that the blocking voltage of each AC power device is clamping to half of the DC-link voltage and the generated harmonics of the three-level rectifier are less than those of the conventional two-level rectifier. There are five voltage levels (0, /spl plusmn/V/sub DC//2, /spl plusmn/V/sub DC/) on the AC side of the diode rectifier. The high power factor and low harmonic currents at the input of the rectifier are verified by software simulations and experimental tests.

Comparison of not synchronized sawtooth carrier and synchronized triangular carrier phase current control for the VIENNA rectifier I

Abstract: Integrated control circuits being available for the input current control of single-phase power factor correctors are frequently applied also for realizing a simple current control for each phase of a three-phase PWM rectifier system. There, the input currents are controlled independently although the three phases are mutually coupled, i.e., the sum of the phase currents is forced to zero for missing connections between the mains star point and the output voltage center point. However, ignoring of the coupling of the three phases results in increased amplitudes of harmonics with switching frequency and/or in a significantly higher ripple of the rectifier input current. This is shown in this paper by a detailed analysis of different current control concepts for a three-phase three-switch three-level boost-type PWM rectifier (VIENNA Rectifier I) with unity power factor. The theoretical considerations are verified by digital simulations and an experimental analysis of a laboratory prototype and are valid in general for three-phase boost-type voltage DC link PWM rectifier systems.

Switch-mode DC power supply, monolithic IC and hybrid IC for the same

Abstract: The switch-mode dc power supply includes a series circuit, a rectifier, an output smoothing circuit, detection circuit, an adding circuit, a triangular wave generator and a control signal generator. The series circuit includes a primary winding of a HF transformer, a semiconductor switching element and a current detection unit connected between two output terminals of a rectifier/smoothing circuit. The rectifier is connected to an end of a secondary winding of the HF transformer. The output smoothing circuit is connected between the rectifier and other end of the secondary winding. The detection circuit is connected to a connection point between the rectifier and the output smoothing circuit. The adding circuit is connected between the detection circuit and a connection point between the semiconductor switching element and the current detection unit. The adding circuit has a current mirror and a current detector. The triangular wave generator is connected to the adding circuit. And the control signal generator is connected between the adding circuit and a control electrode of the semiconductor switching element, and further is connected to the triangular wave generator. The adding circuit adds a voltage corresponding to a dc output signal at the secondary winding to a voltage corresponding to a current flowing in the semiconductor switching element so as to obtain an augmented voltage signal. The gate electrode is supplied with a drive signal keeping the "H" level until the augmented voltage signal reaches the triangular wave signal. Then, the power supply operates with good stability.

Three phase SCR rectifier bridge with soft start control IC

Abstract: A soft start circuit for controlling a rectifier circuit, the rectifier circuit for converting power from an AC source having one or more phases to DC power having an output voltage (Vo) from a Vo+ node to a Vo- node, the rectifier circuit including: (i) at least first and second rectifier legs coupled from the Vo- node to the Vo+ node, each rectifier leg including a diode and a silicon controlled rectifier (SCR), wherein anodes of the diodes are coupled to the Vo- node, cathodes of the diodes are coupled to anodes of the SCRs at AC input nodes, and cathodes of the SCRs are coupled to the Vo+ node; and (ii) a bus capacitor coupled from the Vo+ node to the Vo- node, the soft start circuit operable to control respective firing angles of the SCRs such that: (i) the output voltage substantially linearly ramps from a low initial value to a relatively high final value, and (ii) charge up currents into the bus capacitor are controlled.

A new ZVS semiresonant high power factor rectifier with reduced conduction losses

Abstract: This paper presents a novel single-phase unity power factor rectifier, which features critical conduction mode and zero-voltage switching. The reduced conduction losses are achieved by the employment of a single converter, instead of the typical configuration composed of a front-end rectifier followed by a boost converter. Theoretical analysis, a design example, and experimental results of a 300 W converter with 127 V/sub rms/ input voltage and 400 V/sub DC/ output voltage are presented.

Controlled rectifier bridge with over-voltage protection

Abstract: The present invention relates to a controlled rectifier bridge for a generator comprising several phase windings and an excitation winding, wherein said rectifier bridge is made in the form of an automatic rectifier bridge with field-effect MOS transistors. In order to use such a rectifier bridge with a faster load decrease, and hence with a load-dump voltage, a voltage protection circuit is provided for returning into the battery the energy which has built up in the excitation winding upon a rapid cutoff, thus unloading the excitation winding. In case of a rapid decrease of the load, the windings of the generator are short-circuited by the corresponding triggering of the low- or high-side transistors.

A simple control strategy applied to three-phase rectifier units for telecommunication applications using single-phase rectifier modules

Abstract: This paper presents a simple control technique applied to three-phase rectifier units with high power factor and equilibrated currents in the input. The rectifier unit is composed of three single-phase modules without neutral connection and independent power factor pre-regulation stages. In order to obtain equal power processing in each phase, the output current of each single-phase module needs only to be equal, once the output voltage is common to all of them. The same current in each module is ensured by the current mode control technique. Theoretical analysis of the control technique, along with experimental results are provided in this paper.

Electrostatic discharge protection circuit with high trigger current

Abstract: An ESD protection circuit for protecting a circuit, comprising a lateral semiconductor-controlled rectifier, a MOS transistor, and a current-sinking device. The lateral semiconductor-controlled rectifier is coupled to the circuit and provided with a first common region and a second common region. The MOS transistor integrated with the lateral semiconductor-controlled rectifier includes the first common region The current-sinking device integrated with the lateral semiconductor controlled rectifier includes the second common region. The current-sinking device shunts the majority of a discharge current when the MOS transistor enters breakdown, thereby increasing the trigger current of the lateral semiconductor-controlled rectifier.

Integrated circuit of electronic apparatus

Abstract: PROBLEM TO BE SOLVED: To realize that a power source rectifier diode and a signal detecting diode are mounted in an electronic apparatus integrated circuit. SOLUTION: A P well 2 or an N well 11 is provided electrically independently on an integrated circuit, and MOS transistors of an N or P channel are formed on these wells, and a gate of these transistors is connected to a drain thereof to form a first electrode, to constitute an equivalent diode in which a source is a second electrode. It is possible to decrease the number of parts of electronic apparatuses.

Synchronous rectifier and method of operation

Abstract: A synchronous rectifier circuit ( 10 ) includes a polarity comparator ( 14 ) that generates a signal to a driver circuit ( 16 ) for controlling the voltage at the gate of a power MOSFET ( 60 ). The power MOSFET ( 60 ) is switched to operate in the conduction mode and short out a parasitic diode ( 62 ) when the diode is forward biased. The power MOSFET ( 60 ) is switched to operate in the nonconduction mode when the parasitic diode ( 62 ) is reverse biased. A bias supply circuit ( 12 ) uses a capacitor ( 70 ) to generate a regulated internal bias that provides power to the polarity comparator ( 14 ) and to the driver circuit ( 16 ). The internal bias allows the power MOSFET ( 60 ) to provide a current conduction that is substantially isolated from the changes in voltage levels at the terminals ( 64, 66 ) of the synchronous rectifier circuit ( 10 ).

Boost doubler circuit wherein an AC bridge rectifier is not required

Abstract: A boost doubler circuit is disclosed The circuit comprises an input, a voltage on the input to an output voltage, a transistor arrangement coupled to the input, and a drive circuit coupled to the transistor arrangement for driving The circuit further comprises an output coupled to the drive circuit, for receiving the output voltage, wherein an AC bridge rectifier is not required Through the use of the boost doubler circuit in accordance with the present invention, the full wave rectifier bridge circuit of conventional boost circuitry is not required Furthermore, since the full wave rectifier bridge has been eliminated from the circuit design, the EMC problems related to the rectifier bridge circuit are not prevalent in the present invention and also the additional power dissipation in the rectifier bridge is eliminated This results in a more energy efficient boost circuit configuration

High cell density power rectifier

Abstract: A power rectifier having low on resistance, fast recovery times and very low forward voltage drop. In a preferred embodiment, the present invention provides a power rectifier device employing a vertical device structure, i.e., with current flow between the major surfaces of the discrete device. The device employs a large number of parallel connected cells (26), each comprising a MOSFET structure (10) with a gate to drain short via a common metallization (14). A self aligned body implant (24) and a shallow silicide drain contact region (14) integrated with a metal silicide drain contact define a narrow channel region (16) and allow very high cell density. This provides a low Vf path through the channel regions (16) of the MOSFET cells to the contact (12) on the other side of the integrated circuit. The present invention further provides a method for manufacturing a rectifier device which provides the above desirable device characteristics in a repeatable manner. Also, only two masking steps are required, reducing processing costs.

Power rectifier device and method of fabricating power rectifier devices

Abstract: A power rectifier having low on resistance, mass recovery times and low forward voltage drop. In a preferred embodiment, the present invention provides a power rectifier device employing a vertical device structure, i.e., with current flow between the major surfaces of the discrete device. The device employs a large number of parallel connected cells, each comprising a MOSFET structure with a gate to drain short via a common metallization. This provides a low Vf path through the channel regions of the MOSFET cells to the source region on the other side of the integrated circuit. A thin gate structure is formed annularly around the pedestal regions on the upper surface of the device and a precisely controlled body implant defines the channel region and allows controllable device characteristics, including gate threshold voltage and Vf. A parallel Schottky diode is also provided which increases the switching speed of the MOSFET cells. The present invention further provides a method for manufacturing a rectifier device which provides highly repeatable device characteristics and which can provide such devices at reduced cost. The active channel regions of the device are defined using pedestals in a double spacer, double implant self-aligned process. The channel dimensions and doping characteristics may be precisely controlled despite inevitable process variations in spacer sidewall formation. Only two masking steps are required, reducing processing costs.

Synchronous rectifier having dynamically adjustable current rating and method of operation thereof

Abstract: A synchronous rectifier, a method of operating the same and a power converter incorporating the synchronous rectifier or the method. In one embodiment, the synchronous rectifier includes: (1) a plurality of parallel-coupled active rectifier circuits, each of the plurality of active rectifier circuits having first and second rectifier switches coupled to corresponding first and second voltage limiting switches and (2) a controller, coupled to the plurality of active rectifier circuits, that senses a through-current of the rectifier and employs the voltage limiting switches to disable corresponding ones of the plurality of active rectifier circuits as the through-current decreases to enhance an operating efficiency of the synchronous rectifier.

Rectifying antenna circuit

Abstract: A rectifying antenna circuit for a passive RF transponder comprising a series resonant circuit of an antenna, a voltage rectifier circuit including a diode and a capacitance shunting the diode, the capacitance providing a primary voltage amplification role and the diode providing a rectification and a voltage amplification role.

Boost converter with minimum-component-count active snubber

Abstract: A boost converter includes a novel active snubber which reduces losses caused by the reverse-recovery characteristic of the boost rectifier. The active snubber includes a snubber inductor, a ground-referenced referenced auxiliary switch, and a snubber rectifier. The losses are reduced by inserting the snubber inductor in series with the boost switch and the boost rectifier, so as to control the rate of change (di/dt) of the boost rectifier current during the rectifier's turn-off. A proper operation of the proposed circuit requires overlapping gate drives of the main and the auxiliary switches. The component voltage and current stresses in the proposed circuit are similar to those in the conventional, "hard-switched" boost converter.

A novel simplified space-vector-modulated control scheme for three-phase switch-mode rectifier

Abstract: A novel simplified control scheme for a three-phase switch-mode rectifier is proposed in this paper The proposed control scheme is based upon a load-conductance rectifier controller, in which reference current signals are obtained The goal to follow the reference current is converted to follow a reference voltage A simplified control scheme utilizing space-vector modulation is developed to calculate the duty ratio required to synthesize the reference voltage The proposed scheme has the advantage of space-vector modulation with fast dynamic response and is simple enough to be implemented in a single-chip microprocessor 80196MC