A switch-mode DC converter configured to generate a converted voltage from an input voltage is provided. The switch-mode DC converter includes an inductor configured to store energy, and a switch coupled with the inductor at a switching node, wherein the switch is configurable to be turned on or off to control the discharging of the energy stored at the inductor to an output node of the converter, wherein the output node is configured to provide the converted voltage. The switch-mode DC converter also includes a circuit configured to control a timing of turning-off of the switch based on a voltage difference between the switch, wherein a measurement of the voltage difference is adjusted based on a voltage at the switching node.

A switching device is provided for disconnecting or connecting an electric machine, a converter or a plurality of electrical loads supplied with AC power from a power supply and controlled by a control unit. The switching device includes a current sink and at least one mechanical switch in the switching device are arranged in a circuit. The current sink is arranged, upon receipt of a signal, to close and sink the current, and the at least one mechanical switch is arranged to open and break the current on receipt of a signal to open supplied to the electric machine when the current load is at or close to zero. A method and a computer program for carrying out the method are described.

A switching device is provided for disconnecting or connecting an electric machine, a converter or a plurality of electrical loads supplied with AC power from a power supply and controlled by a control unit. The switching device includes a current sink and at least one mechanical switch in the switching device are arranged in a circuit. The current sink is arranged, upon receipt of a signal, to close and sink the current, and the at least one mechanical switch is arranged to open and break the current on receipt of a signal to open supplied to the electric machine when the current load is at or close to zero. A method and a computer program for carrying out the method are described.

A static transfer switch is provided for supplying power to a load alternately from two different power sources. Switching between the two power sources may occur within a fraction of one electrical cycle. In response to sensing degraded performance in the power source supplying the load, resonant turn off circuits connected directly to the main switches of two phases of the power source are actuated to commutate the respective main switches. The main switch of the third phase is commutated with one or more of the resonant turn off circuits through the delta side of a transformer connected to the three phases of the power source.

An apparatus that physically and electrically attaches to an existing AC electrical switch, and controls the power to the electrical load via outputs from the existing electrical switch or from wireless commands from a remote controller.

The present disclosure provides a DC mechanical circuit breaker that can utilize two switches, one of which can generate zero-crossing with an alternate oscillatory circuit for the other one, which can be a conventional zero-crossing-based AC breaker and can be used in the main circuit. This is different from the conventional single-switch commute-and-absorb method currently used. The present disclosure shows that disclosed circuit breaker improves the fault current extinction and significantly reduces the voltage rate-of-change while creating the current zero-crossing faster compared to the available technology. Thus, disclosed circuit breaker is capable of interrupting high DC currents with minimal arc through a less expensive AC circuit breaker. Simulation and hardware results are provided to show the efficiency of the disclosed circuit breaker.

The present disclosure provides a DC mechanical circuit breaker that can utilize two switches, one of which can generate zero-crossing with an alternate oscillatory circuit for the other one, which can be a conventional zero-crossing-based AC breaker and can be used in the main circuit. This is different from the conventional single-switch commute-and-absorb method currently used. The present disclosure shows that disclosed circuit breaker improves the fault current extinction and significantly reduces the voltage rate-of-change while creating the current zero-crossing faster compared to the available technology. Thus, disclosed circuit breaker is capable of interrupting high DC currents with minimal arc through a less expensive AC circuit breaker. Simulation and hardware results are provided to show the efficiency of the disclosed circuit breaker.

A color temperature switching scheme for an LED lighting device is disclosed. The color temperature switching scheme comprises a plurality of different color temperature performances correspondingly generated by a plurality of different paired combinations of a first electric power allocated to a first LED load emitting a light with a first color temperature and a second electric power allocated to a second LED load emitting a light with a second color temperature such that a mingled color temperature between the first color temperature and the second color temperature can be generated thru a light diffuser. For tuning the mingled color temperature of the LED lighting device a reverse yet complementary power adjustment process for distributing a total electric power T between the first LED circuit and the second LED circuit is required such that a total light intensity remains unchanged while the mingled color temperature is being adjusted.

A color temperature switching scheme for an LED lighting device is disclosed. The color temperature switching scheme comprises a plurality of different color temperature performances correspondingly generated by a plurality of different paired combinations of a first electric power allocated to a first LED load emitting a light with a first color temperature and a second electric power allocated to a second LED load emitting a light with a second color temperature such that a mingled color temperature between the first color temperature and the second color temperature can be generated thru a light diffuser. For tuning the mingled color temperature of the LED lighting device a reverse yet complementary power adjustment process for distributing a total electric power T between the first LED circuit and the second LED circuit is required such that a total light intensity remains unchanged while the mingled color temperature is being adjusted.

A theory and a technical foundation for building a technical framework of a color temperature tuning technology are disclosed, composing a power allocation algorithm and a power allocation circuitry, wherein the power allocation algorithm is a software for designing a process of dividing and sharing a total electric power between at least a first LED load emitting light with a first color temperature CT1 and a second LED load emitting light with a second color temperature CT2 to generate at least one paired combination of a first electric power X allocated to the first LED load and a second electric power Y allocated to the second LED load to create at least one mingled light color temperature CTapp thru a light diffuser according to color temperature tuning formulas CTapp=CT1.Math.X/(X+Y)+CT2.Math.Y/(X+Y) and X+Y=constant; and the power allocation circuitry is a hardware designed for implementing the process.