Hong Kong Applied Science and Technology Research Institute Company, Limited

Tin Ho Li

Sui Pung Cheung

Xin Li

Qing Chun Li

Kin Lap Wong

Qingchun Li

Kuen Fuat Yuen

Kwong Yin Tsang

Chung Yin Lau

Wai To Yan

Described is a method of identifying a short-circuit (SC) like event in a circuit breaker (CB). The method comprises sampling an incoming current to the CB to determine a maximum value of a slope of a curve of the incoming current. The method includes sampling the incoming current again before a level of the incoming current reaches a predetermined, preset, selected, or calculated SC threshold value THfor the CB. The method involves determining from the sampled incoming current that a value of the slope of the incoming current has changed from its maximum slope value to a lower slope value to thereby determine that the incoming current is indicative of a SC like event and does not comprise a real SC event.

Method of identifying a short-circuit like event in a circuit breaker

The invention provides a power converter apparatus for converting an alternating current (AC) power input to a direct current (DC) power output. The apparatus comprises a plurality of n single-phase power converting circuits arranged in parallel, where n is equal to or greater than 2, wherein one of said n single-phase power converting circuits comprises a single-stage AC/DC converter module having an operating AC/DC converter; and each of a remaining n&#x2212;1 of said single-phase power converting circuits comprises a two-stage converter module having an AC/DC converter as an input stage and a DC/DC transformer as an output stage.

Power converter apparatus and a method of modulating thereof

Described is a power connector device for separating an electrical connection under direct current (DC) voltage or alternating current (AC) voltage between an electrical connector element and an electrical contact element. The power connector device includes the electrical contact element. The electrical contact element has a first conductive part and a second conductive part spaced apart one from the other so as not to be directly electrically conductively connected to one another. The power connector device includes a semiconductor switch for maintaining an electrical connection between the electrical connector element and the electrical contact element during separation of contact between said electrical connector element and said first conductive part to thereby prevent arcing during electrical disengagement of the electrical connector element from the electrical contact element. The first conductive part of the electrical contact element is only electrically connected to the second conductive part of the electrical contact element when the semiconductor switch is activated or when the electrical connector element is in contact with both the first and second conductive parts of the electrical contact element.

Digital arc-less connector

An Electrical Protective Device for Low-Voltage DC networks (EPDL) has a controller that on start-up first closes a mechanical relay in a ground line, waits a first delay, then closes a bipolar transistor to allow current to flow through a positive supply line, then turns on a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) connected in parallel with the bipolar transistor once an output voltage reaches a minimum target. The controller reverses the start-up order to open the MOSFET, bipolar transistor, and finally the relay when an over-voltage, input-power, or integrated-current fault is detected. The output current is integrated over time and compared to a threshold, allowing for capacitor charging or other temporary over-loads. When the output voltage dips below the minimum target, the MOSFET is turned off until the voltage recovers. If the voltage does not recover within a time period, the bipolar transistor and then the relay are turned off.

Electrical protective device for low-voltage direct current (LVDC) network

Described is a controller for an AC to DC or a DC to AC multi-phase power converter of a type having N power converter phases, where N is greater or equal to 2. The controller comprises a control module configured to change or vary a phase shift angle of the input current or output current for each of the N power converter phases such that an average phase shift value for each of said N power converter phases over a control module AC line cycle is about, near or substantially the same value. In an embodiment of an AC/DC or a DC/AC multi-phase power converter of a type having N power converter phases arranged in parallel, an advantage of arranging the average phase shift value for each power converter phase to be substantially equal or about equal over an AC line cycle is that it reduces or eliminates any imbalances in the input currents or output currents of the N power converter phases. In preferred arrangements, the control module varies the phase shift angle of the input current or the output current for each of the N power converter phases over each AC line cycle using respective PWM switch control signals.

Controller for an AC/DC or a DC/AC multi-phase power converter

Described is a controller for a DC/DC converter of a type having N power stages, where N is a natural number greater or equal to 2. The controller comprises a decision maker module, a proportional-integral-derivative (PID) or proportional-integral (PI) control module and a transient compression control module. The decision maker module determines a first steady state mode of operation and a second transient mode of operation and is configured to switch control between said first steady state mode of operation to said second transient mode of operation when an operating parameter of one of the N power stages exhibits a predetermined operating condition relative to a predetermined operating limit and/or a predetermined, calculated or selected threshold. The PID or PI module regulates the operating parameter during said first steady state mode of operation. The transient compression control module limits any overshoot, undershoot or imbalances of the operating parameter levels during said second transient mode of operation.

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Hong Kong, China

Tin Ho Li