An AC-voltage sensor circuit is connected to an AC output unit of an inverter circuit. A control circuit and the inverter circuit are isolation-connected. The AC-voltage sensor circuit includes a sense-signal isolation circuit. The inverter circuit and the control circuit are isolation-connected together by the AC-voltage sensor circuit. The AC output unit includes a first line and a second line that are power supply lines. The inverter circuit includes a reference-voltage node. The AC-voltage sensor circuit is configured to output a signal indicating a voltage difference between a “voltage of the first line for the reference-voltage node” and a “voltage of the second line for the reference-voltage node”.

A microgrid comprises an electric vehicle battery storage system that supplies a first DC signal, a bus bar that receives the first DC signal and provides a combined DC signal, a frequency variable and/or voltage variable inverter that receives the combined DC signal, converts, responsive to one or more control signals, the combined DC signal into a first AC signal having variable frequency and/or variable voltage, and provides the first AC signal having the variable frequency and/or voltage to the electrical loads of the facility, and a DC to AC that receives, responsive to the one or more control signals, the combined DC signal from the bus bar, and converts the combined DC signal to a second AC signal.

A micro grid system comprises a secondary energy source and a power controller. The secondary energy source is associated with a micro grid that includes a fixed or mobile facility, and the secondary energy source is configured to generate first DC power signal. The power controller is in communication with the secondary energy source and an electric grid, and configured to receive first AC power signal from the electric grid and the first DC power signal from the secondary energy source and output a second AC power signal to loads in communication with the power controller. The power controller comprises an AC to DC frequency converter configured to change frequency and/or voltage of the second AC power signal, a processor, and a memory configured to store instructions that, when executed, cause the processor to control the frequency converter to change the frequency and/or voltage of the second AC power signal.

A micro grid system comprises a secondary energy source and a power controller. The secondary energy source is associated with a micro grid that includes a fixed or mobile facility, and the secondary energy source is configured to generate first DC power signal. The power controller is in communication with the secondary energy source and an electric grid, and configured to receive first AC power signal from the electric grid and the first DC power signal from the secondary energy source and output a second AC power signal to loads in communication with the power controller. The power controller comprises an AC to DC frequency converter configured to change frequency and/or voltage of the second AC power signal, a processor, and a memory configured to store instructions that, when executed, cause the processor to control the frequency converter to change the frequency and/or voltage of the second AC power signal.

A system comprises a converter that converts a grid AC signal to a first DC signal, a bus bar that receives the first DC signal and provides a combined DC signal, power electronics in communication with electrical loads via a breaker panel, where the power electronics convert, responsive to control signals, the combined DC signal into a second AC signal having variable frequency/variable voltage, and provides the second AC signal to the electrical loads, a processor that receives sensed characteristics and provides, based in part on the sensed characteristics, the control signals to the power electronics, and sensors that sense characteristics of the second AC signal and supply the sensed characteristics to the processor. The power electronics control the variable frequency and/or variable voltage of the second AC signal based at least in part on the one or more control signals to reduce negative effects on the breaker panel.

An apparatus comprises a switch, a current monitor, and a controller. During operation, the switch controls an amount of current through the load. The current monitor samples a magnitude of the current through the load, a magnitude of which varies over time during a time duration. Based on integrating the sample magnitudes of the current through the load over the time duration, the current monitor produces a current sense value. The current sense value is representative of an amount of current through the load. The controller controls an operational state of the switch based upon a comparison of the current sense value with respect to an over-current threshold value. For example, in response to detecting a condition in which the current sense value is greater than the overcurrent threshold value, the controller turns OFF (deactivates) the switch, reducing or eliminating delivery of current through the load.

Methods and apparatus provide for a primary side circuit including one or more voltage nodes; and a monitoring circuit operating to monitor one or more parameters of the primary side circuit, and including at least one sensing circuit and at least one processing circuit within a secondary side circuit, where the sensing circuit includes a resistor network having an input for receiving a first sensed voltage from a first of the voltage nodes of the primary side circuit, traversing an isolation boundary between the primary side circuit and the secondary side circuit while adhering to a safety specification, which includes a primary-secondary isolation requirement, and having an output for providing a first modified sensed voltage to the processing circuit.

Disclosed are apparatus and method for measuring an electric current flowing through an inductive load energized by a half-bridge circuit with at least two semiconductor switches. The semiconductor switches are switched on and off in a complementary manner according to PWM. The apparatus comprises: a monitoring device determining the switched-on states and switched-off states of at least one of the at least two semiconductor switches; a synchronous measurement amplifier controlled by the monitoring device measuring voltage drop at the semiconductor switch during the switched-on state of the semiconductor switch and multiplying it to form multiplied voltage; and a synchronous voltage follower controlled by the monitoring device generating a voltage signal characteristic of the current in the inductive load, which in the switched-on state of the semiconductor switch follows the multiplied voltage and in the switched-off state of the semiconductor switch remains substantially constant or decreases according to a predefined profile.

A system comprises a converter that converts a grid AC signal to a first DC signal, a bus bar that receives the first DC signal and provides a combined DC signal, power electronics in communication with electrical loads via a breaker panel, where the power electronics convert, responsive to control signals, the combined DC signal into a second AC signal having variable frequency/variable voltage, and provides the second AC signal to the electrical loads, a processor that receives sensed characteristics and provides, based in part on the sensed characteristics, the control signals to the power electronics, and sensors that sense characteristics of the second AC signal and supply the sensed characteristics to the processor. The power electronics control the variable frequency and/or variable voltage of the second AC signal based at least in part on the one or more control signals to reduce negative effects on the breaker panel.

A circuit arrangement for monitoring an alternating voltage signal includes a comparator configured to receive the alternating voltage signal or a signal obtained from the alternating voltage signal at a first comparator input and output a comparator signal at a comparator output. The circuit arrangement further includes a zero crossing detector configured to receive a reference signal or a signal obtained from the reference signal at a monitoring input and generate a detector signal at an output of the zero crossing detector. The circuit arrangement further includes a logic circuit including a first timing element connected downstream of the zero crossing detector for generating a first clock signal and a second timing element connected downstream of the zero crossing detector for generating a second clock signal.