The University of Texas System

Mehrdad Ehsani

Thomas Anthony Lipo

Mohammed S Arefeen

A circuit for controlling power to a capacitive load includes a DC power source coupled in series with an inductor and the capacitive load. The inductor provides for resonant charging of the capacitive load from the DC source. A second inductor is used for resonantly discharging the capacitive load back to the power source. Solid state switches are included for selectively activating the charging and discharging of the capacitive load. An energy absorbing load is selectively coupled across the capacitive load to remove any residual voltage after a discharging process.

Capactive power circuit

A series hybrid electric-combustion system is provided which includes an engine (16) operable to generate mechanical energy and translate it to a drive shaft (21). A battery (24) is included that is operable to store electrical energy and to deliver electrical energy. Also provided is a electric machine (18) mechanically coupled to engine (16) and electrically coupled to battery (24). Electric machine (18) has two modes of operations. In the first mode it translates electrical energy from battery (24) into additional mechanical energy at drive shaft (21). In the second mode of operation, electric machine (18) delivers electrical energy to battery (24) for storage. Converter (22) is also included in the system to convert the electrical energy from electric machine (18) for storage and battery (24) and also for converting electrical energy from battery (24) for use by electric machine 18. The system also includes command (12) for inputting system power requirements and controller (14) to control converter (22) and engine (16) in the modes of operation of the system.

Electrically peaking hybrid system and method

A discrete position sensor elimination technique for a sinusoidally wound synchronous reluctance motor drive uses induced voltage, phase currents, and excitation frequency to estimate rotor position at all speeds, including zero speed.

Indirect rotor position sensor for a sinusoidal synchronous reluctance

Apparatus and method for detecting rotor (12) position in a switched reluctance motor (18) having multiple stator phases (A-A', B-B', and C-C'). A multiplexer (48) intermittently connects a known resistor (54) to a non-conducting stator phase. Circuitry (62 and 68) detects the amplitude of the current passing through the resistor (54) and the phase difference between the varying voltage and the current passing through resistor (54). The resulting signal is proportional to the position of rotor (12).

Method and apparatus for sensing the rotor position of a switched

Apparatus and method for detecting rotor (12) position in a switched reluctance motor (18) having multiple stator phases (A--A', B--B', and C--C'). A multiplexer (48) intermittently connects a known resistor (54) to a non-conducting stator phase. Circuitry (62 and 68) detects the amplitude of the current passing through the resistor (54) and the phase difference between the varying voltage and the current passing through resistor (54). The resulting signal is proportional to the position of rotor (12).

A zero current soft switching power converter (10) is provided in which a link capacitor (20) is coupled between a source switch S.sub.1 and a source switch S.sub.2. The reversal of voltage polarity across link capacitor (20) allows for zero current switching of switches S.sub.1 and S.sub.2.

Power conversion using zero current soft switching

An inverse dual converter circuit (20) provides continuous voltage step-up or step-down control over a wide range and without the need of a transformer. The converter comprises an input DC voltage source (22) for generating an input DC voltage. An inverse dual converter bridge receives the input DC voltage and comprises a network of source voltage converters (26), an AC link circuit (28), and a network of load voltage converters (32). The source voltage converters (26) and load voltage converters (32) operate at the same frequency, but at a different phase. The AC link circuit (28) stores energy to be transferred from the source voltage converters (26) to the load voltage converters (32) and supplies reverse voltage bias for commutation. The inverse dual DC-DC (20) converter may include circuitry (180) for controlling the output DC voltage and for regulating output current continuity. Topological variations of the basic circuit include transformer coupled (140), multi-phase (80) and multi-pulse derivations. The single-phase inverse dual converter circuit (20) offers a buck-boost operation over a wide range without a transformer, bi-directional power flow, and complimentary commutation of converters. The commutation mechanism provided in the inverse dual converter circuit (20), when combined with gate turn-off switch thyristors provides zero current switching. This allows operation at high frequencies in high-power applications, with high efficiency.

Inverse dual converter for high-power applications

Rotor position information for a switched reluctance (SR) motor drive is obtained indirectly in response to the motor phase inductance. An oscillator generates a signal having a time period that is a function of the inductance. The signal is processed by other circuits to obtain proper instants of commutation. In the preferred motor drive, the energized phase windings are isolated from the oscillator, and periodic signals are obtained which have periods indicating the phase inductances of the unenergized phase windings. The periods are compared to threshold values to obtain position indicating signals, and commutating signals are derived from the position indicating signals.

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Bryan, TX, United States of America

Mehrdad Ehsani