Abb Schweiz Ag

Abb Research Ltd.

Abb Technology Ag

Georgia Tech Research Corporation

University of Missouri

Clemson University

Jiaqi Liang

Li Qi

Jiuping Pan

Wen Ouyang

Harish Suryanarayana

Frans Dijkhuizen

Alireza Nami

Anil K Kondabathini

Darren Dale Tremelling

Tomas Lars Jonsson

Zhenyuan Wang

Zhiguo Pan

Jyoti Sastry

Ronald Gordon Harley

Debrup Das

Liwei Wang

Ganesh Kumar Venayagamoorthy

Jukka Pekka Kittila

Unique systems, methods, techniques and apparatuses for a ZVT ZCT resonant converter with a variable resonant tank are disclosed. One exemplary embodiment is a system comprising a bidirectional resonant converter comprising an input/output terminal, a switching device coupled with the input/output terminal, a resonant circuit coupled with the switching device and including a variable inductor, an output/input terminal coupled with the resonant circuit, and a DC biasing circuit operatively coupled with the variable inductor. The variable inductor comprises a toroidal core, a first winding wound around the toroidal core and coupled with the switching device and the output/input terminal, a second core structured to overlap a portion of the toroidal core, and a second winding wound around the second core and coupled with the DC biasing circuit. The DC biasing circuit is controllable to vary the inductance of the variable inductor by saturating a portion of the toroidal core.

Variable inductor apparatuses systems and methods

A control apparatus and corresponding control method use per-unit filtering in a plurality of power-sharing controllers, to obtain a power-sharing command signal for respective ones among a plurality of different energy storage units in a hybrid energy storage system. The hybrid energy storage system includes two or more types of energy storage units and the power-sharing command signal for each energy storage unit is obtained by filtering an input signal using a filter having a filter response that is tailored to the energy storage characteristics of the energy storage unit. The input signal reflects load variations on the electrical grid and may be locally generated or provided by a remote node. While the power-sharing control loops used for each energy storage unit advantageously may be the same in terms of architecture and implementation, each loop uses tailored, dedicated filtering and, possibly, individualized values of one or more other control parameters.

Method and apparatus for controlling a hybrid energy storage system

A multilevel converter converting between AC and DC includes a phase leg having a first and a second phase arm, the first phase arm being connected between a first pole having a first potential and a first AC terminal and the second phase arm being connected between the first AC terminal and a second potential, where the phase arms include half-bridge and full-bridge cells, where each cell includes at least one energy storage element for providing the voltage contribution and cell switching units with cell switches and anti-parallel diodes for controlling the voltage contribution, where the full-bridge cells include a bypass switch controllable to bypass the corresponding energy storage element, and when a phase-to-ground fault occurs the cell switches are blocked and the bypass switches activated with a delay in relation to the blocking.

Multilevel converter with reduced AC fault handling rating

Resonant converters with variable inductor

Unique systems, methods, techniques and apparatuses of zero-voltage transition pulse width modulation resonant converters are disclosed. One exemplary embodiment is a zero-voltage transition PWM resonant converter comprising a DC bus, a first switching device, a second switching device, a resonant tank circuit, an auxiliary circuit having a flying capacitor and a plurality of auxiliary switching devices, and a controller. The controller is structured to control the first switching device, the second switching device, and the plurality of auxiliary switching devices to provide resonant operation of the tank circuit effective to provide a substantially zero voltage condition across the first switching device when turning the first switching device on or off and to provide a substantially zero voltage condition across the second switching device when turning the second switching device on or off.

Resonant converters including flying capacitors

According to one aspect of the teachings herein, a system for obtaining electricity from wind turbines provides advantageous operation with respect to offshore wind turbines where the size and weight of electricity generation and collection equipment are key considerations. The contemplated system includes an apparatus that is configured for collecting wind-generated electricity at a fixed low frequency and at a desired collection voltage, based on the advantageous configuration and use of a modular multilevel converter or MMC.

Method and apparatus for obtaining electricity from offshore wind turbines

A power distribution system for off-shore natural resource platforms includes an off-shore medium voltage direct current (MVDC) power bus. The MVDC power bus includes multiple power bus segments, each of which may be connected to one or more other power bus segments via a corresponding circuit breaker. Each power bus segment may also be electrically coupled to an off-shore renewable energy source, such as a wind farm, and/or an off-shore drilling platform. The off-shore drilling platforms may include local power distribution systems electrically connected to a corresponding power bus segment via a circuit breaker to receive power from the MVDC power bus and supply power to local equipment of the off-shore drilling platform.

Power distribution system for off-shore natural resource platforms

A generation and distribution system includes an adjustable-speed prime mover and a doubly-fed asynchronous alternating-current (AC) generator driven by the prime mover and having a first poly-phase circuit, e.g., a stator, and a second poly-phase circuit, e.g., a rotor. The system further includes a first AC bus electrically coupled to the first poly-phase circuit configured to deliver AC power at a first AC voltage to multiple loads, and a second AC bus connected to the second poly-phase circuit configured to deliver AC power at a second AC voltage to another group of loads, the second AC voltage being lower than the first. The system includes a poly-phase transformer having first windings electrically coupled to the first AC bus and having second windings electrically coupled to the second AC bus, and a poly-phase AC-to-AC electronic converter circuit electrically coupled between the second poly-phase circuit and the second AC bus.

Doubly-fed, variable-speed, dual-voltage AC generation and distribution systems

A system includes a first DC rail and a second DC rail, and a rectifier coupled with the first and second DC rails. A multilevel converter is also coupled with the DC rails and operable to limit input current harmonics to the rectifier. Differences between voltage phase and current phase in AC electrical power supplied to the system are compensated via closed loop control of a voltage output of the multilevel converter.

System for converting AC electrical power to DC electrical power and methods

Technologies for reducing peak fault output current in a DC power generation system include a generator having a reduced damper winding and a controller to control a rectifier array to generate a DC power output. In some embodiments, the generator may have no damper windings, may have damper windings including a reduced number of damper bars, and/or may have damper windings having separated end ring mounts for each damper bar. The controller is configured to control the rectifier array so as to reduce oscillations of the DC output that may be due to the reduced damper windings. To do so, the controller is configured to generate the control signal based on an oscillation component of the DC power output. For example, the controller may generate an oscillation correction signal based on the DC power output and adjust a firing angle set point of the rectifier array based on the oscillation correction signal.

Reducing peak fault output current in a DC power generation system

A dynamic stochastic optimal power flow (DSOPF) control system is described for performing multi-objective optimal control capability in complex electrical power systems. The DSOPF system and method replaces the traditional adaptive critic designs (ACDs) and secondary voltage control, and provides a coordinated AC power flow control solution to the smart grid operation in an environment with high short-term uncertainty and variability. The DSOPF system and method is used to provide nonlinear optimal control, where the control objective is explicitly formulated to incorporate power system economy, stability and security considerations. The system and method dynamically drives a power system to its optimal operating point by continuously adjusting the steady-state set points sent by a traditional optimal power flow algorithm.

Method and system for dynamic stochastic optimal electric power flow control

A protection device includes a diode having its forward direction in a normal power flow of a region of a DC collection system, a first switch in parallel with the diode, a second switch in series with the diode and a control unit for controlling the switches. The first switch can be opened so that current can flow through the diode in the forward direction without the first switch bypassing the diode, and closed if no current is flowing through the diode in the forward direction and power is needed upstream of the diode. The second switch can be closed so that current can flow through the diode in the forward direction to an AC grid interface of the DC collection system, and opened if no current is flowing through the diode in the forward direction due to a fault in a DC feeder to which the device is coupled.

Protection device for DC collection systems

In one aspect of the teachings herein, a self-commutated current source converter is operated in a manner that compensates for the reactive power consumption and/or harmonics generation of a line-commutated current source converter used in the transfer of electrical power between an AC power system and a DC power system. In this regard, the line-commutated current source converter is operated as a first converter in a hybrid converter apparatus and the self-commutated current source converter is operated as a second converter in the hybrid arrangement. According to one example, the first and second converters are stacked, such that each shares a portion of the DC voltage on the DC side of the hybrid converter apparatus, while in another example, the second converter is not used for power conversion and instead is used solely for compensation with respect to the first converter.

Growing community of inventors

Cary, NC, United States of America

Jiaqi Liang