Abstract: A precharge system for precharging a DC bus circuit includes a first input, first and second circuit branches, and a controller, where the first circuit branch includes a first contactor between the first input and an AC to DC converter, the second circuit branch has: a disconnect switch coupled to the first input; a variable frequency drive (VFD) with an AC input coupled to the disconnect switch; an inductor coupled to an AC output of the VFD; and a second contactor coupled to the inductor. The precharge VFD provides precise control of the precharge operation such as charging time, current limiting, short-circuit and ground fault protection, monitoring DC Bus capacitance and verifies the health of the shared DC bus circuit through startup diagnostic.

Abstract: A precharge system for precharging a DC bus circuit includes a first input, first and second circuit branches, and a controller, where the first circuit branch includes a first contactor between the first input and an AC to DC converter, the second circuit branch has: a disconnect switch coupled to the first input; a variable frequency drive (VFD) with an AC input coupled to the disconnect switch; an inductor coupled to an AC output of the VFD; and a second contactor coupled to the inductor. The precharge VFD provides precise control of the precharge operation such as charging time, current limiting, short-circuit and ground fault protection, monitoring DC Bus capacitance and verifies the health of the shared DC bus circuit through startup diagnostic.

Abstract: A filter for reducing radiated emissions in switching power converters such as a motor drive is disclosed. The switching power converter modulates a DC voltage input to generate a desired AC voltage output. Capacitors are connected in parallel between each output phase and a common connection, which may be a ground connection. The magnitude and layout of the capacitors are selected to minimize current conducted by the capacitors. The capacitors may be surface mount technology located proximate to the switching devices or the capacitors may be incorporated in the circuit board on which the switching devices are mounted. The filter may be applied to any of the switching elements in a motor drive, such as the inverter section, an active rectifier section, or a switched mode power supply.

Abstract: A method is provided for detection of a ground fault in a high resistance network in a voltage source power conversion circuit comprising a power converter that converts incoming AC power to DC power applied to a DC bus and an inverter that converts DC power from the DC bus to output AC power. The method includes detecting a midpoint-to-ground voltage between a low side of the DC bus and a ground potential and detecting the presence of a ground fault in a high resistance network based upon the detected midpoint-to-ground voltage.

Abstract: A filter for reducing radiated emissions in switching power converters such as a motor drive is disclosed. The switching power converter modulates a DC voltage input to generate a desired AC voltage output. Capacitors are connected in parallel between each output phase and a common connection, which may be a ground connection. The magnitude and layout of the capacitors are selected to minimize current conducted by the capacitors. The capacitors may be surface mount technology located proximate to the switching devices or the capacitors may be incorporated in the circuit board on which the switching devices are mounted. The filter may be applied to any of the switching elements in a motor drive, such as the inverter section, an active rectifier section, or a switched mode power supply.

Abstract: A filter for reducing radiated emissions in switching power converters such as a motor drive is disclosed. The switching power converter modulates a DC voltage input to generate a desired AC voltage output. Capacitors are connected in parallel between each output phase and a common connection, which may be a ground connection. The magnitude and layout of the capacitors are selected to minimize current conducted by the capacitors. The capacitors may be surface mount technology located proximate to the switching devices or the capacitors may be incorporated in the circuit board on which the switching devices are mounted. The filter may be applied to any of the switching elements in a motor drive, such as the inverter section, an active rectifier section, or a switched mode power supply.

Abstract: A method is provided for detection of a ground fault in a high resistance network in a voltage source power conversion circuit comprising a power converter that converts incoming AC power to DC power applied to a DC bus and an inverter that converts DC power from the DC bus to output AC power. The method includes detecting a midpoint-to-ground voltage between a low side of the DC bus and a ground potential and detecting the presence of a ground fault in a high resistance network based upon the detected midpoint-to-ground voltage.

Abstract: A method is provided for detection of a ground fault in a high resistance network in a voltage source power conversion circuit comprising a power converter that converts incoming AC power to DC power applied to a DC bus and an inverter that converts DC power from the DC bus to output AC power. The method includes detecting a midpoint-to-ground voltage between a low side of the DC bus and a ground potential and detecting the presence of a ground fault in a high resistance network based upon the detected midpoint-to-ground voltage.

Abstract: A filter for reducing radiated emissions in switching power converters such as a motor drive is disclosed. The switching power converter modulates a DC voltage input to generate a desired AC voltage output. Capacitors are connected in parallel between each output phase and a common connection, which may be a ground connection. The magnitude and layout of the capacitors are selected to minimize current conducted by the capacitors. The capacitors may be surface mount technology located proximate to the switching devices or the capacitors may be incorporated in the circuit board on which the switching devices are mounted. The filter may be applied to any of the switching elements in a motor drive, such as the inverter section, an active rectifier section, or a switched mode power supply.

Abstract: A method is provided for detection of a ground fault in a high resistance network in a voltage source power conversion circuit comprising a power converter that converts incoming AC power to DC power applied to a DC bus and an inverter that converts DC power from the DC bus to output AC power. The method includes detecting a midpoint-to-ground voltage between a low side of the DC bus and a ground potential and detecting the presence of a ground fault in a high resistance network based upon the detected midpoint-to-ground voltage.

Abstract: The present invention is directed to an auxiliary circuit for reducing low order current harmonics in a three-phase drive system driving a single-phase load, the three-phase drive system including a three-phase source voltage connected to a rectifier system connected to a DC link choke inductor connected to a three-phase current source inverter system.

Abstract: A compensator circuit for reducing low order current harmonics in a three-phase drive system driving a single-phase load, the three-phase drive system including a three-phase source voltage connected to a rectifier system connected to a DC link capacitor connected to a three-phase voltage source inverter that supplies three-phase power.

Abstract: The present invention is directed to a compensator-filter circuit for reducing low order current harmonics in a three-phase drive system driving a single-phase load, the three-phase drive system including a three-phase source voltage connected to a rectifier system connected to a DC link capacitor connected to a three-phase voltage source inverter.

Abstract: A rectifier includes a transformer, a rectifying bridge, a link capacitor, and at least a first resonance loop. The transformer is operable to receive three phase input signals having a source frequency and generate a plurality of transformer phase signals. The rectifying bridge has a number of stages corresponding to the number of transformer phase signals and is operable to generate a rectified output signal based on the transformer phase signals. The link capacitor is coupled across the rectifying bridge. The first resonance loop is coupled between the rectifying bridge and the link capacitor. The first resonance loop has a first resonance frequency corresponding to a harmonic frequency of the source frequency.

Abstract: A modular inductor arrangement is provided in which a footprint of an enclosure for single or multiple phase inductors provides enhanced thermal transfer. The inductor coil may be wound about an axis generally parallel to a mounting surface of the package, so as to provide for reduced height and expanded footprint dimensions. The inductor package may be mounted on a thermal support, such as a fluid-cooled support. Heat is extracted from the assembly during operation, so as to establish a reduced maximum internal temperature as compared to here for known structures. The arrangement may be included in various circuit configurations, such as power converters. Other components may be incorporated and integrated into the package, including sensors, capacitor coils, other inductor coils, and so forth.

Abstract: The present invention provides an improved inductor design which bounces thermal requirements with magnetic and other requirements. The package is designed based upon the desired magnetic volume and the dimensions of a primary heat dissipation surface, which is preferably designed for conductive heat transfer during operation. The other dimensions, such as the height of the package, result from these two parameters. Optimized package designs may thus be obtained which provide the desired operating temperatures, while better utilizing the magnetic volume. Package designs may include new aspect ratios, such as ratios providing a base area greater than a lateral side area. Aspect ratios between base dimensions, such as a diameter in cylindrical package and the resulting height may also be characteristic of the inductors resulting from the novel design approach.

Abstract: A termination network to be used with an induction motor for eliminating voltage reflections and voltage surges due to voltage reflections, the network includes a resistive element in series with a capacitive element between each two voltage supply lines. The capacitive element initially operates like a short so that a resistive element terminates each line for a short period, the termination network impedance matches the line impedance, and reflection is eliminated. After a voltage pulse passes to a stator winding the capacitor element is charged and the resistive element is effectively removed from the line circuit.

Abstract: A transformer including a core; a concentric inner primary tube passing through the core and running up and over at least a portion of the core, the concentric inner primary tube defining a longitudinal axis within the core; and a concentric outer secondary tube passing through the core and running up and over the concentric inner primary tube, the concentric outer secondary tube defining a longitudinal axis within the core and being spaced apart from the concentric inner primary tube, the longitudinal axis of the concentric inner primary tube and the longitudinal axis of the concentric outer secondary tube being aligned with one another so as to be coaxial. The concentric outer secondary tube substantially encloses the concentric inner primary tube so as to provide a low impedance shield.

Abstract: A capacitor precharge circuit limits both peak DC link current and peak AC line current to any desired peak magnitude thereby providing for optimum precharge control and robust operation. The precharge circuit employs a microprocessor which implements a non-linear discontinuous current control scheme without the need for current sensors. The precharge circuit is well suited for use with an AC to DC converter having link inductor and a DC bus capacitor which requires precharging before full power is applied to the converter.

Abstract: A harmonic compensator comprises a transformer having low leakage reactance connected between a utility and a load and a signal generator which injects into the transformer a signal having a frequency which cancels undesirable higher order harmonics induced by the load. The low leakage reactance nature of the transformer permits injection of high frequency signals which restore the fundamental sine wave of the signal from the utility and thereby eliminates undesirable nonlinear harmonics which cause up-line disruptions. The low leakage reactance transformers may comprise a coaxial structure having a thin hollow tube as the primary coil, a coaxial structure having a single main coaxial cable distributed into several paralleled coaxial cables of smaller diameter, or a co-planar transformer structure having flat strip line conductors wrapped around a conventional core as the primary and secondary coils.