General Electric Company

Rik W De Doncker

Robert Dean King

Paul Michael Szczesny

James Patrick Lyons

Mustansir Hussainy Kheraluwala

Peter Claudius Sanza

Kenneth B Haefner

Venkatagiri Venkataramanan

A GTO gate driver circuit includes a GTO; a MOS gate driver; a turn-on rectifier for receiving power from a high voltage isolation transformer; a turn-on capacitor coupled in parallel with the turn-on rectifier; and a turn-on MOSFET having a drain coupled to a first side of the turn-on capacitor, a gate coupled to the MOS gate driver, and a source coupled to a gate of the GTO. In one embodiment the circuit includes a turn-off rectifier coupled to the turn-on rectifier; a turn-off capacitor coupled in parallel to the turn-off rectifier with a cathode of the GTO being coupled to a second side of the turn-on capacitor and a first side of the turn-off capacitor; and a turn-off MCT having a gate coupled to the MOS gate driver, an anode coupled to the source of the MOSFET and a cathode coupled to a second side of the turn-off capacitor. In an alternative embodiment the circuit includes a turn-off rectifier; a turn-off capacitor coupled in parallel to the turn-off rectifier; and a turn-off MCT having a gate coupled to the MOS gate driver, an anode coupled to one side of the turn-off capacitor, and a cathode coupled the cathode of the GTO. Either embodiment may further include a detection logic unit for evaluating the current to monitor for GTO failure conditions or for modulating the current for information transfer to the MOS gate driver.

GTO gate driver circuits for snubbered and zero voltage soft switching

A torque shudder protection device for an induction machine includes a flux command generator for supplying a steady state flux command and a torque shudder detector for supplying a status including a negative status to indicate a lack of torque shudder and a positive status to indicate a presence of torque shudder. A flux adapter uses the steady state flux command and the status to supply a present flux command identical to the steady state flux command for a negative status and different from the steady state flux command for a positive status. A limiter can receive the present flux command, prevent the present flux command from exceeding a predetermined maximum flux command magnitude, and supply the present flux command to a field oriented controller. After determining a critical electrical excitation frequency at which a torque shudder occurs for the induction machine, a flux adjuster can monitor the electrical excitation frequency of the induction machine and adjust a flux command to prevent the monitored electrical excitation frequency from reaching the critical electrical excitation frequency.

Torque shudder protection device and method

An ac electric drive system includes a bidirectional power semiconductor interface between a battery, or an auxiliary energy storage device, and a power inverter for boosting an input dc voltage and for decoupling the dc link voltage from the input dc voltage such that the dc link voltage is substantially independent of the input dc voltage and the parameters of the battery or energy storage device. The input dc voltage is controlled to maximize efficiency along predetermined torque envelopes.

Technique for decoupling the energy storage system voltage from the DC

A dual active bridge converter, including high-frequency transformer-coupled input and output bridge converters, receives a rectified ac line voltage via a rectifier acting in a resistive mode and a small, high-frequency filter capacitor. A phase angle controller controls a phase shift between the voltages across the transformer windings such that high-efficiency dc-to-dc conversion is achieved, while maintaining unity power factor at the ac input, using high-density circuitry with small filter components and without adding additional front-end power factor correction circuitry.

Unity power factor control for dual active bridge converter

A current regulator for a four-legged, three-phase inverter determines the next optimal, or near-optimal, inverter state in a relatively short time period based on phase current error signals and back-emf's, resulting in low harmonic distortion, reduced current ripple, minimal current stresses, and increased utilization of the available dc bus voltage over a high bandwidth.

Current regulator for a four-legged three-phase inverter

A torque feedback system is employed in a universal field-oriented (UFO) controller to tune a torque-producing current command and a slip frequency command in order to achieve robust torque control of an induction machine even in the event of current regulator errors and during transitions between pulse width modulated (PWM) and square wave modes of operation.

Closed-loop torque feedback for a universal field-oriented controller

The direct (d) and quadrature (q) components of flux, as sensed by flux sensors or determined from voltage and current measurements in a direct field orientation scheme, are processed rapidly and accurately to provide flux amplitude and angular position values for use by the vector rotator of a universal field-oriented (UFO) controller. Flux amplitude (linear or squared) is provided as feedback to tune the UFO controller for operation in direct and indirect field orientation modes and enables smooth transitions from one mode to the other.

High speed flux feedback for tuning a universal field oriented

A method for controlling a power converter and an associated auxiliary commutation circuit ensures soft-switching of all switching devices employed therein. Such a power converter includes an inverter with at least two main switching devices per phase. Across each main switching device are connected an antiparallel diode and a relatively large snubber capacitor. The auxiliary resonant commutation circuit comprises two antiparallel-coupled auxiliary switching devices coupled in series with a resonant circuit including an inductor and the snubber capacitors. The gating and conduction times of the main and auxiliary switching devices are controlled so as to add boosting energy to the resonant operation, thus ensuring that the inverter output voltage at least reaches the positive and negative inverter rail voltages during each resonant commutation cycle. As a result, the control achieves commutation of the converter pole with substantially no switching losses.

Method for controlling a power converter using an auxiliary resonant

A single-phase, soft-switching, ac-to-dc power converter comprises a rectifier for receiving and rectifying an ac voltage and providing the rectified ac voltage to a boost dc-to-dc converter, which in turn is coupled to an active clamped resonant dc link (ACRDCL). Resonant oscillations of the resonant dc link circuit comprising an inductor and a capacitor are maintained via control of an active clamp switching device. Soft-switching in a discrete pulse modulation scheme is achieved by controlling the switching instants of a boost switching device to occur at zero voltage instants of the resonant dc link. Alternatively, if a pair of snubber capacitors are added to the boost converter, soft-switching may be achieved in a pulse width modulation mode, resulting in reduced subharmonics even at higher frequencies and with smaller filter components.

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Schenectady, NY, United States of America

Rik W De Doncker