A bidirectional switch for the control of power from an AC source to a load is described. The approach uses power MOSFETs in a bidirectional switch subcircuit configuration having an optically coupled, electrically floating control circuit that self-biases the switches into the on state and uses an optically coupled control element to force the switches into the off state. The time constant of the control circuit is fast enough to allow phase control as well as on-off control. A boost circuit is included to ensure that the control voltage exceeds a threshold voltage of the MOSFETs to force an off state. A plurality of subcircuits can be easily cascaded to provide improved performance.

A bidirectional switch for the control of power from an AC source to a load is described. The approach uses power MOSFETs in a bidirectional switch subcircuit configuration having an optically coupled, electrically floating control circuit that self-biases the switches into the on state and uses an optically coupled control element to force the switches into the off state. The time constant of the control circuit is fast enough to allow phase control as well as on-off control. A boost circuit is included to ensure that the control voltage exceeds a threshold voltage of the MOSFETs to force an off state. A plurality of subcircuits can be easily cascaded to provide improved performance

A power supply control device according to one or more embodiments may be provided to: control a power conversion device that has a configuration in which a resonant circuit is provided on an output side of a matrix converter including switching circuits having snubber elements, and that performs AC-AC conversion of output from a multi-phase AC power supply. The power supply control device performs control such that: the output current, which has a phase difference caused by the resonant circuit, is negative during a period in which an absolute value of a positive-going output voltage that is output from the power conversion device increases while the output current is positive during a period in which the absolute value of a negative-going output voltage increases; and a polarity of the output current does not change within a period in which the snubber element is discharged.

Embodiments of the present disclosure provide multi-mode phase control dimmers for lighting devices, particularly for use with wireless lighting control systems. The disclosed universal dimming devices include a load-type detection circuit for determining whether the load for connected lighting devices has an inductive characteristic. The system automatically detects the load characteristic and self-adjusts its phase-cut dimming mode in response. The disclosed solutions require minimal additional components to provide load-type detection beyond those components already included in typical phase dimming applications, particularly in a wireless lighting control environment, thereby minimizing cost. The disclosed solutions have improved reliability by detecting multiple characteristics detected for each of a plurality of AC cycles in order to reliably distinguish between load types.

The present invention provides a multi-load control apparatus, a slave circuit and a control method thereof. The multi-load control apparatus includes a master circuit and at least one slave circuit. The master circuit generates at least one pulse width modulation (PWM) signal according to an input signal. The slave circuit controls a power switch according to a corresponding PWM signal. The slave circuit has a primary side circuit and a secondary side circuit. The primary side circuit generates an AC PWM signal according to the corresponding PWM signal. The power switch has a control terminal which is driven according to a floating ground level which is not a constant voltage level. The power switch has a current inflow terminal and a current outflow terminal, which are connected to a corresponding load circuit in series, wherein the series circuit of the power switch and the load circuit receives an AC voltage.

An AC-AC power converter, such as a motor soft starter, includes an input connectable to an AC source with a disconnect switch, an output connectable to an AC load, and phase lines connecting the input and output to transmit power. In-line solid-state switching blocks are connected between line terminals and load terminals of the AC source and AC load, respectively, such that each phase line includes a solid-state switching block connected thereto. Free-wheeling solid-state switching blocks are connected to the load terminals at one end and together at a common connection at another end, such that each phase line includes a free-wheeling solid-state switching block connected thereto. Each of the in-line and free-wheeling solid-state switching blocks comprises a bi-directional switching block that selectively controls current and withstands voltage in both directions. The switching blocks also provide soft-starter functions, variable speed control, and integrated circuit breaker protection capability.

A power management apparatus 20 comprises a first energy harvesting input channel 21; a first energy storage element connection 25; an inductor connection 27; and a switching circuit 28. A controller 30 is configured to operate the switching circuit 28 to transfer energy between the first energy harvesting input channel 21 and the first energy storage element connection 25 by a sequence of energy transfer cycles. Each of the energy transfer cycles comprises an energise phase in which energy is transferred from the first energy harvesting input channel 21 to the inductor connection 25 for an energise time (tE) and a de-energise phase. The first energy harvesting input channel 21 is capable of receiving an AC electrical signal and a DC electrical signal. The controller 30 is configured to determine a type of an electrical signal received at the first energy harvesting input channel 21, where the type is one of an AC electrical signal and a DC electrical signal, and determine an energise time (tE) and a harvesting cycle period (tP) for the switching circuit 28 based on the determined type.

A power controller system comprises multiple power controllers that receive a periodic waveform input and that apply power to multiple loads. A switch-on time and a switch-off time is for each of the power controllers within a cycle of the periodic waveform input. The power controllers generate output waveforms to be applied to the loads that are partial segments of the cycle of the periodic waveform input. Each of the power controllers includes a switchable power component that can be switched on and switched off at any time and that can conduct current in both forward and reverse directions.

A power management apparatus 20 comprises a first energy harvesting input channel 21; a first energy storage element connection 25; an inductor connection 27; and a switching circuit 28. A controller 30 is configured to operate the switching circuit 28 to transfer energy between the first energy harvesting input channel 21 and the first energy storage element connection 25 by a sequence of energy transfer cycles. Each of the energy transfer cycles comprises an energise phase in which energy is transferred from the first energy harvesting input channel 21 to the inductor connection 25 for an energise time (tE) and a de-energise phase. The first energy harvesting input channel 21 is capable of receiving an AC electrical signal and a DC electrical signal. The controller 30 is configured to determine a type of an electrical signal received at the first energy harvesting input channel 21, where the type is one of an AC electrical signal and a DC electrical signal, and determine an energise time (tE) and a harvesting cycle period (tP) for the switching circuit 28 based on the determined type.

A dimmer circuit for detecting a connected load type comprising a controller, a plurality of dimming transistors adapted to provide a dimmed hot output signal to a load, and a current sensor adapted to sense current levels of the dimmed hot output signal. The controller is adapted to store at least one load type current parameter associated with a dimming mode. The controller is further adapted to generate an asymmetric forward phase transistor drive signal with half cycles of one polarity having incrementally increasing dimming levels to drive the plurality of dimming transistors. The controller receives current levels from the current sensor and determines whether at least one of the received current levels satisfies at least one stored current parameter. When at least one current level satisfies at least one current parameter, the controller sets the dimmer to operate in a dimming mode associated with the satisfied current parameter. When the received current levels do not satisfy the stored at least one load type current parameter, the controller sets the dimmer to operate in a default dimming mode. The at least one current parameter may define one or more current events associated with a load type, such as an inrushing current event, double peaked current event, a lagging current event, or a substantially non-ratiometric current rise.