Abstract: A battery state detection method includes: presetting at least one discharge method and at least one discharge condition of a battery set for estimating a battery state, with the discharge condition including a discharge voltage, discharge time or a relative battery impedance variation; executing a partial discharge procedure of the battery set and measuring partial discharge data; and directly calculating battery state data of the partial discharge data under the discharge method and the discharge condition. The battery state data include a SOH (state of health) datum, a SOC (state of charge) datum or a residual discharging time datum. The detection of the battery set is suitable for a manual operation system, a remote control monitoring system or an automatic scheduling system.

Abstract: A power generation abnormality detection method includes operating a power converter to controllably operate a solar cell module at a plurality of predetermined voltage points to obtain a plurality of measured currents, utilizing the predetermined voltage points and measured currents to calculate a plurality of first power data, comparing the plurality of first power data with a first PV curve, or operating the power converter to controllably operate the solar cell module at a plurality of predetermined current points to obtain a plurality of measured voltages, utilizing the predetermined current points and measured voltages to calculate a plurality of second power data, and comparing the plurality of second power data with a second PV curve.

Abstract: A multi-level DC-DC converter device includes an inverter, a 3-winding high-frequency transformer, a first full-bridge rectifier, a second full-bridge rectifier, a selective circuit and a filter circuit. A first winding at a primary side of the high-frequency transformer connects with the inverter while a second winding and a third winding of at a secondary side of the high-frequency transformer connect with the first full-bridge rectifier and the second full-bridge rectifier. The selective circuit connects with DC output ports of the first full-bridge rectifier and the second full-bridge rectifier, thereby operationally selecting two serially-connected full-bridge rectifiers or single full-bridge rectifier to output two voltage levels performed as a multi-level output voltage. The filter circuit connects between the selective circuit and a load for filtering harmonics and outputting a DC voltage.

Abstract: A DC-DC converter is operated in a boost mode by operating a plurality of low-voltage side switches with a first fixed duty cycle (greater than 0.5), with cutting off a plurality of the first high-voltage side switches and a plurality of the second high-voltage side switches, with conducting a plurality of the first diodes of the first high-voltage side switches and a plurality of the second diodes of the second high-voltage side switches, and with alternatively conducting and cutting off a bidirectional switch. In a buck mode, the low-voltage side switches are cut off and a plurality of diodes of the low-voltage side switches are conducted. Furthermore, the first high-voltage side switches are complemented and are operated with a second fixed duty cycle (less than 0.5) while the second high-voltage side switches are conducted and cut off alternatively and the bidirectional switch is switched on and off.

Abstract: A multi-port energy storage system includes a bi-directional power conversion circuit, a DC-AC inverter circuit, an electric energy storage facility, a first AC port, a second AC port and an AC switch. The multi-port energy storage system controllably provides various classifications of power supply quality via the first AC port and the second AC port.

Abstract: A double-port energy storage system includes a bi-directional power conversion circuit, a DC-AC inverter circuit, an electric energy storage facility, a first switch, a second switch, a third switch, a fourth switch, a first AC port and a second AC port. The double-port energy storage system controllably provides various classifications of power supply quality by controllably switching on or off some of the first switch, the second switch, the third switch the fourth switch via the first AC port and the second AC port.

Abstract: A rapid cutoff device includes a thyristor AC switch for supplying an AC current from a first AC circuit to a second AC circuit. A serially-connected circuit of a first switch and a first capacitor parallel-connects with the first AC circuit. A serially-connected circuit of a second switch and a second capacitor parallel-connects with the second AC circuit. When cutting off the thyristor AC switch, the first switch is operated to conduct the first capacitor in a first direction for the AC current charging to the first capacitor, alternatively, the second switch is operated to conduct the second capacitor in a second direction for the AC current charging to the second capacitor, thereby lowering a current in the thyristor AC switch approaching a zero value and thus rapidly cutting off it.

Abstract: A shadowing compensation device for a solar cell module has an input port, an isolated DC-DC power converter, and an output port. The input port is connected to two output ends of a solar cell array including multiple solar cell modules connected in series. The output port is connected to one of the multiple solar cell modules of the solar cell array. When one of the solar cell modules connected to the output port of shadowing compensation device has been shaded, the isolated DC-DC power converter outputs a compensating current to the solar cell module that has been shaded for increasing the output voltage of the solar cell module that has been shaded, and increasing the output voltage and output power of the solar cell array.

Abstract: A multilevel AC/DC power converter device includes a high-frequency power converter including a first AC port and a low-frequency power converter including a second AC port and a DC port. A power converting method includes: serially connecting the first AC port of the high-frequency power converter and the second AC port of the low-frequency power converter; operating frequency of the low-frequency power converter synchronized with frequency of an AC power source and operating the high-frequency power converter with high-frequency PWM to generate a multilevel AC voltage; and controlling the multilevel AC voltage to obtain a current of an input AC port being sinusoidal and in a same phase with a voltage of the AC power source. Accordingly, the input power factor approaches unity and the low-frequency power converter supplies a DC voltage to a load via a DC output port.

Abstract: A cascade bridge-type DC-AC power converter device includes a low-frequency bridge-type power converter including an AC terminal and a DC bus and a high-frequency bridge-type power converter including an AC terminal. A power conversion method includes: serially connecting the AC terminal of the high-frequency bridge-type power converter and the AC terminal of the low-frequency bridge-type power converter; operating frequency of the low-frequency bridge-type power converter synchronized with frequency of an AC source; and operating the high-frequency bridge-type power converter with high-frequency PWM to generate a multilevel AC voltage. A DC power source connects to the DC bus of the low-frequency bridge-type power converter. No additional power supply circuit will be required for power supply to a DC bus of the high-frequency bridge-type power converter. Accordingly, the power circuit is simplified, and the manufacturing cost is reduced.

Abstract: A rapid cutoff device includes a thyristor DC switch, a switch and a capacitor. An operation method includes: connecting the thyristor DC switch between a first DC circuit and a second DC circuit; serially connecting the switch and the capacitor which further parallel connects the first DC circuit; when the thyristor DC switch is conducted, supplying a DC current via the thyristor DC switch; when a drive signal of the thyristor DC switch stops, operating the switch to conduct the capacitor which is charged by the first DC circuit to rapidly lower a current of the thyristor DC switch approaching a zero value, thereby rapidly cutting of the thyristor DC switch.

Abstract: A control method for bidirectional DC-DC converter includes: operating a bidirectional DC-DC converter having a low voltage side including a plurality of low-voltage-side switches, a voltage clamping switch and a voltage clamping capacitor, and a high voltage side including a plurality of high-voltage-side switches in a boost mode; switching the voltage clamping switch with a predetermined duty cycle prior to switching on all of the low-voltage-side switches; adjusting the predetermined duty cycle of the voltage clamping switch to be smaller than a turn-off interval of the low-voltage-side switches to reduce the conduction loss of the low-voltage-side switches and the voltage clamping switch; alternatively, operating the DC-DC converter in a buck mode; and adjusting and extending the duty cycle of the low-voltage-side switches to overlap a turn-off time of the high-voltage-side switches to reduce the conduction loss of the low-voltage-side switches.

Abstract: A shadowing compensation device for solar cell module has an input port, an isolated DC-DC power converter, and an output port. The input port is connected to two output ends of a solar cell array comprised of multiple solar cell modules connected in series. The output port is connected to one of the multiple solar cell modules of the solar cell array. When one of the solar cell modules connected to the output port of shadowing compensation device has been shaded, the isolated DC-DC power converter outputs a compensating current to the solar cell module been shaded for increasing the output voltage of the solar cell module been shaded, and increasing the output voltage and output power of the solar cell array.

Abstract: A five-level DC-AC converter includes a capacitor set and a full-bridge circuit. The capacitor set contains two DC capacitors, a power electronic switch and two diodes. When the power electronic switch is turned on/off, the two DC capacitors are connected in series/parallel to provide a two-level DC voltage to the full-bridge circuit. The full-bridge circuit further converts the two-level DC voltage to output a voltage with three voltage levels in the positive half cycle and three voltage levels in the negative half cycle. This achieves the goal of using five power electronic switches to convert DC power into AC power with five voltage levels.

Abstract: An estimation method for residual discharging time of batteries includes the steps of: providing a set of battery-discharge-current intervals and a set of battery-discharge equations, setting the discharge time of each battery-discharge-current intervals at zero; detecting a discharge current, voltage and time of batteries; judging whether the discharge current exceeds all of the battery-discharge-current intervals; selecting one of the battery-discharge-current intervals and the associated battery-discharge equation according to the detected discharge current; calculating an estimation of residual discharging time; accumulating and recording the discharge time; judging whether the discharge voltage is lower than a predetermined value and calculating an estimation error of the residual discharging time; and adjusting parameters of the battery-discharge equation for reducing the estimation error of the residual discharging time if the estimation error is greater than a predetermined error value.

Abstract: A cascade bridge-type DC-AC power converter device includes a low-frequency bridge-type power converter including an AC terminal and a DC bus and a high-frequency bridge-type power converter including an AC terminal. A power conversion method includes: serially connecting the AC terminal of the high-frequency bridge-type power converter and the AC terminal of the low-frequency bridge-type power converter; operating frequency of the low-frequency bridge-type power converter synchronized with frequency of an AC source and operating the high-frequency bridge-type power converter with high-frequency PWM to generate a multilevel AC voltage. A DC power source connects to the DC bus of the low-frequency bridge-type power converter. No additional power supply circuit will be required for power supply to a DC bus of the high-frequency bridge-type power converter. Accordingly, the power circuit is simplified and the manufacturing cost is reduced.

Abstract: A multilevel AC/DC power converter device includes a high-frequency power converter including a first AC port and a low-frequency power converter including a second AC port and a DC port. A power converting method includes: serially connecting the first AC port of the high-frequency power converter and the second AC port of the low-frequency power converter; operating frequency of the low-frequency power converter synchronized with frequency of an AC power source and operating the high-frequency power converter with high-frequency PWM to generate a multilevel AC voltage; controlling the multilevel AC voltage to obtain a current of an input AC port being sinusoidal and in same phase with a voltage of the AC power source. Accordingly, the input power factor approaches unity and the low-frequency power converter supplies a DC voltage to a load via a DC output port.

Abstract: A bi-directional DC to DC power converter includes two DC sources, two inductors respectively connected to the two DC sources, a first switch and a second switch respectively connected to the two inductors, two capacitors respectively connected to the two switches, and a third switch connected between the two inductors. The first, second and third switches are respectively connected reversely with a diode in parallel. When the third switch is alternately turned on and off and the first and second switches are always turned off, the power converter operates as a boost power converter and electric energy flows from the two DC sources to the two capacitors. When the third switch is always turned off and the first and second switches are synchronously turned on or off, the power converter operates as a buck power converter and electric energy flows from the two capacitors to the two DC sources.

Abstract: A UPS system includes one or more UPS units with identical or different capacities. A control circuit, used to control a DC/AC inverter of the UPS unit, includes a voltage feedback control circuit and a current feedforward control circuit. The voltage feedback control circuit is used to control the amplitude and the waveform of load voltage. The current feedforward control circuit is used to operate the DC/AC inverter of the UPS unit as a virtual fundamental resistor and a virtual harmonic resistor which are serially connected to an output terminal of the DC/AC inverter such that each UPS unit can be distributed to provide an output current according to the capacity ratio of the UPS system.

Abstract: A battery-charging device, having a maximum power point tracking (MPPT) function, for a stand-alone generator system includes a DC/DC power converter and a control circuit used to control the DC/DC power converter.