Legacy automatic variable capacitor KVAR compensation systems typically use either electromechanical devices such as relays or contactors of various forms and types to switch the selected capacitors in and out of the electrical system under some form of electronic control. These systems are slow and discontinuous in their ability to closely regulate the exact value of compensatory capacitance needed to compensate the variable and rapidly changing reactive power KVAR in the electrical power transmission and distribution networks. The present invention provides a fast response active KVAR compensator based on a variable transimpedance topology.

A step-down AC/AC converter for use in an electric distribution system includes at least one chopper circuit for each one of a plurality of phases of the AC power, each chopper circuit including a four-quadrant switch coupled in series between primary and secondary sides of the chopper circuit and a current-bidirectional two-quadrant switch coupled between the secondary side of the chopper circuit and a common node. Each current-bidirectional two-quadrant switch is oriented in the same direction, with respect to the secondary side of the corresponding chopper circuit and the common node. The converter further includes a control circuit configured to pulse-width-modulate control inputs of the switches, to convert a first multiphase AC voltage at the primary sides of the chopper circuits to a second multiphase AC voltage at the secondary sides of the chopper circuits, the second multiphase AC voltage being lower in voltage than the first multiphase AC voltage.

A step-down AC/AC converter for use in an electric distribution system includes at least one chopper circuit for each one of a plurality of phases of the AC power, each chopper circuit including a four-quadrant switch coupled in series between primary and secondary sides of the chopper circuit and a current-bidirectional two-quadrant switch coupled between the secondary side of the chopper circuit and a common node. Each current-bidirectional two-quadrant switch is oriented in the same direction, with respect to the secondary side of the corresponding chopper circuit and the common node. The converter further includes a control circuit configured to pulse-width-modulate control inputs of the switches, to convert a first multiphase AC voltage at the primary sides of the chopper circuits to a second multiphase AC voltage at the secondary sides of the chopper circuits, the second multiphase AC voltage being lower in voltage than the first multiphase AC voltage.

A power supply device includes a DC power supply circuit to output a DC voltage, an AC power supply circuit to generate an AC voltage, and a power supply control circuit to control the DC power supply circuit and the AC power supply circuit. The AC power supply circuit outputs a superimposed voltage in which the DC voltage is superimposed with the AC voltage. The power supply control circuit controls the DC power supply circuit to output the DC voltage according to a DC output value corresponding to the AC voltage.

A power supply device includes a DC power supply circuit to output a DC voltage, an AC power supply circuit to generate an AC voltage, and a power supply control circuit to control the DC power supply circuit and the AC power supply circuit. The AC power supply circuit outputs a superimposed voltage in which the DC voltage is superimposed with the AC voltage. The power supply control circuit controls the DC power supply circuit to output the DC voltage according to a DC output value corresponding to the AC voltage.

A converter including a converter control for a wind turbine and a chopper, wherein the converter control includes a dynamic limit value which is allowable for a first tolerance time and a static limit value of the converter. Furthermore, an overcurrent module is provided which includes a limit value expander which is designed to increase the static limit value by a portion of the difference from the dynamic limit value as additional current, and a dynamic module which interacts with the limit value expander in such a way that overcurrents between the static limit value which is increased by the additional current and the dynamic limit value are routed in a first stage to the converter and in a second stage at least partially to the chopper, wherein a switch is made to the second stage after a second tolerance time.

A converter including a converter control for a wind turbine and a chopper, wherein the converter control includes a dynamic limit value which is allowable for a first tolerance time and a static limit value of the converter. Furthermore, an overcurrent module is provided which includes a limit value expander which is designed to increase the static limit value by a portion of the difference from the dynamic limit value as additional current, and a dynamic module which interacts with the limit value expander in such a way that overcurrents between the static limit value which is increased by the additional current and the dynamic limit value are routed in a first stage to the converter and in a second stage at least partially to the chopper, wherein a switch is made to the second stage after a second tolerance time.

A method and an electronic device for power allocation of multi-parallel power electronic transformers, the method including: determining a quantity of conversion stages of the power electronic transformers; obtaining a load ratio-efficiency relationship between the two ports of each conversion stage in turn, performing a curve fitting to obtain a load ratio-efficiency curve of each conversion stage of the power electronic transformers; calculating a load ratio-loss relationship of each conversion stage, based on the load ratio-efficiency curve of each conversion stage; obtaining a multi-parallel minimum-operation-loss power allocation curve of each conversion stage; performing a piecewise curve fitting of the minimum-operation-loss power allocation curve to obtain a multi-parallel optimum power allocation mathematical model of each stage; and determining an optimum power allocation to each port of the multi-parallel power electronic transformers, based on the multi-parallel optimum power allocation mathematical model of each stage.

A power supply system includes a power control device and a power supply device. The power control device includes a first controller, a power measurement circuit, and a first communication circuit. The power measurement circuit measures power being supplied to the power supply device. The first controller calculates additionally suppliable power based on the power being supplied and selects one operation mode based on the additionally suppliable power. The first communication circuit transmits the operation mode selected to the power supply device. The power supply device includes a second controller, a power converter circuit, and a second communication circuit. The second communication circuit receives the operation mode selected. The second controller outputs a condition of supply power indicating electric power supplied, to the power converter circuit. The power converter circuit converts electric power based on the condition of supply power, and supplies the electric power converted to an external device.

A control module is able to be installed with electrical devices, such as, for example electrical loads (e.g., lighting loads) and/or load regulation devices. The control module may determine whether an LED driver for an LED light source is responsive to one or more of a plurality of control techniques. The control module may be able to automatically determine an appropriate control technique to use to control the connected LED driver and/or LED light source. The control module may sequentially attempt to control the LED driver and/or LED light source using each of the plurality of control techniques and determine if the LED driver and/or LED light source is responsive to the present control technique. The plurality of control techniques may include one or more analog control techniques and one or more digital control techniques.