A power supply device is disclosed. A circuit board is disposed inside a conductive housing. A rectifying module is disposed on the circuit board and has primary and secondary sides. The grounding module includes a first grounding element, a second grounding element, and a fastening element. Two terminals of the first surge protection module are respectively electrically connected to the primary side and the first grounding element. Two terminals of the second surge protection module are respectively electrically connected to the secondary side and the second grounding element. The second grounding element and the first grounding element are not directly connected. The fastening element passes through the conductive housing, the circuit board, the first grounding element, and the second grounding element so that the conductive housing, the first grounding element, and the second grounding element are electrically connected to one another.

A power supply device is disclosed. A circuit board is disposed inside a conductive housing. A rectifying module is disposed on the circuit board and has primary and secondary sides. The grounding module includes a first grounding element, a second grounding element, and a fastening element. Two terminals of the first surge protection module are respectively electrically connected to the primary side and the first grounding element. Two terminals of the second surge protection module are respectively electrically connected to the secondary side and the second grounding element. The second grounding element and the first grounding element are not directly connected. The fastening element passes through the conductive housing, the circuit board, the first grounding element, and the second grounding element so that the conductive housing, the first grounding element, and the second grounding element are electrically connected to one another.

Virtual oscillator control systems, devices, and techniques are provided. One example device includes a processor configured to implement a virtual oscillator circuit and output an oscillating waveform based on the virtual oscillator circuit and power electronics operatively coupled to the processor and configured to convert, based on the oscillating waveform, direct current (DC) electricity to alternating current (AC) electricity. The processor may be further configured to extract, from the virtual oscillator circuit, a virtual current based on an output current of the AC electricity, and output the oscillating waveform further based on an input voltage of the DC electricity.

A DC-to-AC power conversion system includes DC power source assemblies each having a plurality of DC power sources and a combiner coupled to the DC output from the DC power source assemblies. A power inverter is coupled to a DC output of the combiner and configured to invert the DC output to an AC output. The system includes a controller programmed to identify a potential ground fault using current data received from a ground current sensor provided on a ground conductor. After identifying the faulty DC power source using sensed current data received from a current sensor provided on at least one of the positive conductors and the negative conductors, the controller opens the DC breaker switches on a positive conductor and a negative conductor of the combiner to disconnect the faulty DC power source assembly from the power inverter.

An uninterruptible power supply (UPS) system (100) comprises a plurality of UPS units (UPS-1, UPS-2) connected in parallel. The controllers (130) of the units are programmed to implement a voltage calibration procedure and a current calibration procedure, in order that measurements of voltage and current made by sensors within the different units will agree. In the current calibration procedure, the load is disconnected (302) while one of the units is selected as a master and operates in a voltage control mode (VCM) (Steps 304-308). Each other unit is selected in turn and operated in a current control mode (310, 312). Current measurements made in the master unit are communicated (314) via a data bus to the selected unit and compared (316) with measurements made in the unit itself. The unit adapts its current sensing gains to match the master unit.

An uninterruptible power supply (UPS) system (100) comprises a plurality of UPS units (UPS-1, UPS-2) connected in parallel. The controllers (130) of the units are programmed to implement a voltage calibration procedure and a current calibration procedure, in order that measurements of voltage and current made by sensors within the different units will agree. In the current calibration procedure, the load is disconnected (302) while one of the units is selected as a master and operates in a voltage control mode (VCM) (Steps 304-308). Each other unit is selected in turn and operated in a current control mode (310, 312). Current measurements made in the master unit are communicated (314) via a data bus to the selected unit and compared (316) with measurements made in the unit itself. The unit adapts its current sensing gains to match the master unit.

A power management method includes measuring the voltage and the current of a power source, an electrical output and a battery. The power generated by the power source, the power consumed by the electrical output and the power exchanged with the battery are calculated. The power source, the electrical output, the battery and the electrical grid are connected. Measurements of electrical generation and information on the consumption and control possibility of one or more remote systems are transmitted to a monitoring device. The electrical output is connected to the power source, the battery or the electrical grid according to information on the tariff per kWh provided by the public electricity grid, such as

During measuring an insulation resistance for an inverter having at least one half-bridge including two active switching elements for driving an output current, and a DC link voltage, a center point of the half-bridge positioned between the switching elements is connected to a grounding point by closing a grounding switch, and the center point connected to the grounding point is connected, one after the other, to a first ungrounded terminal and a second ungrounded terminal of the DC link voltage of the inverter present at the half-bridge by means of the two active switching elements of the half-bridge to establish a connection between the first and second ungrounded terminals, respectively, and the grounding point. A current flowing via the connection to the grounding point is measured using a measuring device.

During measuring an insulation resistance for an inverter having at least one half-bridge including two active switching elements for driving an output current, and a DC link voltage, a center point of the half-bridge positioned between the switching elements is connected to a grounding point by closing a grounding switch, and the center point connected to the grounding point is connected, one after the other, to a first ungrounded terminal and a second ungrounded terminal of the DC link voltage of the inverter present at the half-bridge by means of the two active switching elements of the half-bridge to establish a connection between the first and second ungrounded terminals, respectively, and the grounding point. A current flowing via the connection to the grounding point is measured using a measuring device.

An apparatus and a method of determining a frequency of an AC power source that more accurately determine the frequency of the AC power source connected to a vehicle are provided. The apparatus includes a rectifier that is connected to the AC power source to rectify an AC voltage input from the AC power source, a first filter connected to an output terminal of the rectifier to filter a rectified voltage output by the rectifier and a second filter connected to the output terminal of the rectifier to filter the rectified voltage output by the rectifier. Further, a frequency determination unit configured to receive the rectified voltages that pass through the first and second filters and determine a voltage frequency of the AC power source from the rectified voltage that pass through the first filter using the rectified voltage that pass through the second filter as a frequency determination level.