A testing device is provided. The testing device comprises a processor and a switching AC to AC power converter that has no DC link. The processor is configured to set a plurality of bi-directional switches in the power converter in a configuration of on/off states that cause a substantially set electric current to flow through a component being tested by the testing device.

Power converters, and microgrids driven by such a power converter, in which the converter is controlled by a proportional controller which operates directly on AC waveforms, preferably without conversion to a DC type signal; preferably with use of voltage compensation to remove inherent error of proportional controller; and preferably with use of individual phase RMS voltages in the voltage compensation, to allow for normal operation under any load condition. Undervoltage of one or two phases is automatically compensated by adjusting the voltage of all phases, to retain balance. Line-starting of a motor load is automatically detected, and frequency droop is driven, apart from the other control relations in the system, to complete the line-starting operation as quickly as possible.

The method of controlling power transmission to a load permits: to eliminate over-voltage in an electric circuit; to decrease energy losses and time of charging of an energy storing device; to increase service life of switches and provide very high reliability of power transmission to a load. The conception is following: controlling power transmission to a load from additional circuit so that current can be transferred from additional circuit to operating circuit (circuit with a load) and vice versa from operating circuit to additional circuit without interruption (without switching off) circuit of the load.

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.

In a power conversion device, a constant voltage can be supplied even when the voltage of an alternating current power supply fluctuates. A switching element Q1 and switching element Q2 are connected to a direct current power supply series circuit. A connection point of a direct current power supply and direct current power supply is a neutral point terminal, a connection point of the switching element Q1 and switching element Q2 is an output terminal, switch elements S1 and S2 are connected between the output terminal and neutral point terminal, switch elements S3 and S4 are connected between a terminal R of an alternating current power supply having a terminal S connected to the neutral point terminal, and the output terminal, and a first element and second element selected from among the switching elements Q1 and Q2 and switch elements S1 to S4 are turned on and off complementarily.

A bidirectional switch and dimmer 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 that includes a floating AC/DC power supply and a solid state double pole switch that alternates between connection of the AC source to the load and periodic connection of the AC source to the AC/DC power supply. The switch and dimmer circuit configuration allows insertion into an existing single-phase circuit using only two wires. The design allows for manufacturing the entire circuit on a single chip.

A constant-voltage drive device capable of adjusting output voltage includes a chopping wave structure, an AC power voltage detection module, an AC voltage signal bias module, a power factor correction controller with multiplier, a power factor correction and energy conversion and transmission module, an output control module, a reference signal generation module, an AC power phase angle detection module and a phase angle information transmission module. The output voltage can be both constant and adjustable, so that the output changes with the phase angle information of input, and also provides the chopping wave structure with current for proper functioning. The device is applicable for bigger power range with better compatibility and stronger adaptability.

A power controller for an AC power converter connected in series with a load and receiving power from or delivering power to a power source, the power controller comprising: a radial control block controlling a radial component of an electrical parameter of the AC power converter; and a chordal control block controlling a chordal component of the electrical parameter of the AC power converter. Also provided is a power system comprising one or more loads each connected in series to a power converter each controlled by a power controller as described above. There is also provided a method of controlling an AC power converter connected in series with a load and receiving power from a power source, the method comprising: controlling a radial component of an electrical parameter of the AC power converter; and controlling a chordal component of the electrical parameter of the AC power converter.

A method may include processing a first signal derived from an input signal with a first path to generate a first path voltage at a first path output, processing a second signal derived from the input signal with a second path to generate a second path voltage at a second path output, the second path comprising a linear amplifier having at least one transistor for driving the second path voltage, generating the first signal and the second signal with a signal splitter, such that the second signal comprises information of the input signal absent from the first signal, and such that the second path voltage is of a sufficient magnitude such that the at least one transistor operates in a saturation region of the at least one transistor throughout a dynamic range of a load voltage equal to the difference of the first path voltage and the second path voltage.

An alternating current power electronic converter includes an alternating current chopper circuit including two pairs of switches, each switch of a pair connected in series and the two pairs of switches connected in parallel. Each switch of a pair is a uni-directional switch. The uni-directional switches of each pair are arranged in opposing directions, and the uni-directional switches of one pair of switches are arranged in an opposing configuration to the uni-directional switches of the other pair of switches. The circuit comprises a bridge connection between switches of each pair of switches. A controller is configured to control a sequence of operation of the switches, providing an overlap period whenever one of the switches of a pair changes from open to closed and the other switch of the pair changes from closed to open. During the overlap period the switch that is moving from closed to open remains closed.