The present invention provides a line interactive UPS, which comprises an AC input, an AC output, a chargeable and dischargeable device, a DC/AC inverter, a rectifying circuit, a full-bridge inverter, a capacitor, a switch, a charger, a boost circuit and a rectifying and buck circuit. An output of the boost circuit is connected to an input of the full-bridge inverter. The rectifying and buck circuit is controlled to provide a rectified output or a rectified and voltage-decreased output. An input of the rectifying and buck circuit is connected to the AC input. The rectifying and buck circuit is operative to provide a pulsating DC to the boost circuit or the full-bridge inverter. The line interactive UPS of the present invention can provide a stable AC to the AC output and has the advantages of small size and low cost.

An objective of the invention to provide a hybrid converter station for HVDC system and the method operating the same. The hybrid rectifier station for high voltage direct current system includes: at least one AC bus; at least one line commutated converter configured to convert a portion of AC power supplied from the at least one AC bus to DC power transmitted on HVDC transmission line of the high voltage direct current system thereby generating reactive power demand; and at least one voltage source converter; wherein: the at least one line commutated converter and the at least one voltage source converter are coupled in parallel to the HVDC transmission line; and the at least one voltage source converter is configured to compensate the reactive power demand via the parallel coupling while converting another portion of the AC power supplied from the at least one AC bus to DC power transmitted on the HVDC transmission line. By reusing the VSC supplying both of the active power for power transmission and reactive power for LCC reactive power compensation, it is helpful for raising the total active AC power rating of the HVDC transmission system without incorporating extra power conversion device or changing the design of LCC. Besides, the nominal DC voltage of LCC and VSC is the same and the power flow shifting process is not needed.

An objective of the invention to provide a hybrid converter station for HVDC system and the method operating the same. The hybrid rectifier station for high voltage direct current system includes: at least one AC bus; at least one line commutated converter configured to convert a portion of AC power supplied from the at least one AC bus to DC power transmitted on HVDC transmission line of the high voltage direct current system thereby generating reactive power demand; and at least one voltage source converter; wherein: the at least one line commutated converter and the at least one voltage source converter are coupled in parallel to the HVDC transmission line; and the at least one voltage source converter is configured to compensate the reactive power demand via the parallel coupling while converting another portion of the AC power supplied from the at least one AC bus to DC power transmitted on the HVDC transmission line. By reusing the VSC supplying both of the active power for power transmission and reactive power for LCC reactive power compensation, it is helpful for raising the total active AC power rating of the HVDC transmission system without incorporating extra power conversion device or changing the design of LCC. Besides, the nominal DC voltage of LCC and VSC is the same and the power flow shifting process is not needed.

A DC link capacitor in a drive system for an electric vehicle is quickly discharged using only local action within an inverter module and without any extra components to dissipate the charge. The inverter has a phase leg comprising an upper switching device and a lower switching device coupled across the capacitor. A gate driver is coupled to the phase leg to alternately switch the switching devices to ON state according to a PWM signal during pulse-width modulation of the drive system. The gate driver is configured to discharge the link capacitor during a discharge event by simultaneously activating the upper and lower switching devices to transitional states. Thus use of transitional states ensures that the switching devices provide an impedance that dissipates the capacitor charge while protecting the devices from excessive temperature.

A DC link capacitor in a drive system for an electric vehicle is quickly discharged using only local action within an inverter module and without any extra components to dissipate the charge. The inverter has a phase leg comprising an upper switching device and a lower switching device coupled across the capacitor. A gate driver is coupled to the phase leg to alternately switch the switching devices to ON state according to a PWM signal during pulse-width modulation of the drive system. The gate driver is configured to discharge the link capacitor during a discharge event by simultaneously activating the upper and lower switching devices to transitional states. Thus use of transitional states ensures that the switching devices provide an impedance that dissipates the capacitor charge while protecting the devices from excessive temperature.

The present disclosure relates to accumulating electrical energy and the teachings thereof may be embodied in accumulator systems and methods. For example, an accumulator system may comprise: an energy accumulator for generating a DC voltage; a converter for converting the DC voltage into an AC voltage, connected to the energy accumulator via an intermediate circuit; and a diode in the intermediate circuit connected in parallel with the energy accumulator and the converter. The diode may have reverse bias to limit a voltage in the intermediate circuit.

The present disclosure relates to accumulating electrical energy and the teachings thereof may be embodied in accumulator systems and methods. For example, an accumulator system may comprise: an energy accumulator for generating a DC voltage; a converter for converting the DC voltage into an AC voltage, connected to the energy accumulator via an intermediate circuit; and a diode in the intermediate circuit connected in parallel with the energy accumulator and the converter. The diode may have reverse bias to limit a voltage in the intermediate circuit.

A vehicle system in a hybrid vehicle comprises a controller configured to generate for output a modulated voltage to a direct current capacitor to prevent voltage spikes on the capacitor in response to receiving a reference current via a direct current voltage clamping control block that outputs a reference current in response to a difference between a feedback voltage and a reference voltage exceeding a threshold.

A vehicle system in a hybrid vehicle comprises a controller configured to generate for output a modulated voltage to a direct current capacitor to prevent voltage spikes on the capacitor in response to receiving a reference current via a direct current voltage clamping control block that outputs a reference current in response to a difference between a feedback voltage and a reference voltage exceeding a threshold.

Systems and methods for electrical power conversion include the provision of a full-bridge tunnel diode inverter topology which provides a balanced push-pull drive voltage and current across the entire transformer primary. Moreover, the full-bridge tunnel diode inverter may avoid operating its tunnel diodes in a high-current/high-voltage state at light loads, unlike a single-diode inverter. The disclosed principles also allow a full-bridge tunnel diode inverter topology that may avoid RF chirps in the tunnel diodes during rising or falling device ramp currents since the primary current passes through two tunnel diodes in series.