Abstract: A reactive power compensator device includes an AC capacitor and a small-capacity power converter serially connected thereto that avoid the problems of power resonance and harmonic current injection. The reactive power compensator device provides with compensation reactive power current with fixed amplitude or adjustable amplitude. The power converter permits one of power lines of a power system to be connected to either a positive or negative dc terminal of the power electronic switch set through no power electronic switch. Consequently, the number of the power electronic switches is reduced.

Abstract: A harmonic-suppressing AC/DC power converter employs a control method for permitting the AC/DC power converter only to detect an input AC current and an output DC voltage. The control method can control the AC side of the AC/DC power converter to generate a voltage which is proportional to the input AC current. Thereby, the AC/DC power converter acts as a virtual resistor having a linear resistance characteristic. Accordingly, the input AC current of the AC/DC power converter can be controlled to approximate nearly as a sinusoidal wave with the performance of high input power factor and low input harmonic current.

Abstract: An apparatus for supporting a video camera includes a camera mounting bracket, a front handle assembly and a rear handle assembly. The camera mounting bracket has an L-shaped profile and includes a handle mounting shelf and a camera mounting shelf. The camera mounting shelf and the front handle assembly are attached to the front of the handle mounting shelf. The rear handle assembly is attached to the rear of the handle mounting shelf at a position between the front handle assembly and the camera mounting shelf. Consequently, the apparatus will help a person to firmly hold a video camera when using the video camera to record scenes, regardless of different heights of view.

Abstract: A three-phase three-wire active power filter includes a dc power capacitor, a power converter, a filter inductor set, a reactive power compensating capacitor set, a combined capacitor/resistor filtering set and a control circuit. The dc power capacitor provides with a regulated voltage. The power converter includes a two-arm bridge power converter, and has a pair of ac terminals and a pair of dc terminals. A phase of the three-phase three-wire active power filter, without control of the power electronic switch set, directly connects with any one of the dc terminals. Consequently, the number of power electronic switches employed in the two-arm bridge power converter of the three-phase three-wire active power filter can be reduced.

Abstract: An active type harmonic suppression apparatus, connected in parallel to a power feeder, supplies a compensation current for injecting into the power feeder such that a utility current of a power source is approached to a sinusoidal wave. The control circuit retrieves a load current, a utility current, an output current of the power converter, a power source voltage and a voltage of the dc power capacitor for calculating and sending a reference signal of compensation voltage to a pulse-width-modulation circuit which generates switching signals for the power converter. Furthermore, the harmonic suppression apparatus can provide a fixed or variable reactive power.

Abstract: A three-phase three-wire active power filter includes a dc power capacitor, a power converter, a filter inductor set, a reactive power compensating capacitor set, a combined capacitor/resistor filtering set and a control circuit. The dc power capacitor provides with a regulated voltage. The power converter includes a two-arm bridge power converter, and has a pair of ac terminals and a pair of dc terminals. A phase of the three-phase three-wire active power filter, without control of the power electronic switch set, directly connects with any one of the dc terminals. Consequently, the number of power electronic switches employed in the two-arm bridge power converter of the three-phase three-wire active power filter can be reduced.

Abstract: A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator comprises a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and is adapted to supply a current with a nearly sinusoidal waveform. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.

Abstract: An apparatus for supporting a video camera includes a camera mounting bracket, a front handle assembly and a rear handle assembly. The camera mounting bracket has an L-shaped profile and includes a handle mounting shelf and a camera mounting shelf. The camera mounting shelf and the front handle assembly are attached to the front of the handle mounting shelf. The rear handle assembly is attached to the rear of the handle mounting shelf at a position between the front handle assembly and the camera mounting shelf. Consequently, the apparatus will help a person to firmly hold a video camera when using the video camera to record scenes, regardless of different heights of view.

Abstract: A bi-directional dc/dc power converter having a neutral terminal includes a first dc voltage terminal set and a second dc voltage terminal set. When the direction of power flow is from the first dc voltage terminal set to the second dc voltage terminal set, the Output voltage of power converter is the double of the input dc voltage. When the power flow direction is in reverse from the second dc voltage terminal set to the first dc voltage terminal set, the output voltage of power converter is half of the input dc voltage in this power flow direction.

Abstract: A reactive power compensator device includes an AC capacitor and a small-capacity power converter serially connected thereto that avoid the problems of power resonance and harmonic current injection. The reactive power compensator device provides with compensation reactive power current with fixed amplitude or adjustable amplitude. The power converter permits one of power lines of a power system to be connected to either a positive or negative dc terminal of the power electronic switch set through no power electronic switch. Consequently, the number of the power electronic switches is reduced.

Abstract: A power converter for a hybrid power filter includes a power electronic switch set and a DC capacitor. The power converter permits a power line of a power system to directly connect or connect through the passive power filter to a positive or a negative terminal of the DC capacitor of the power converter for free control of the power electronic switches. Consequently, the power converter has a lesser number of the power electronic switches that can reduce the manufacture cost.

Abstract: A control method for the parallel-connected power converters includes a control circuit comprising a voltage feedback circuit and a current feed-forward circuit. The voltage feedback circuit, consisting of a voltage regulated control circuit and a waveform control circuit, is used to control the power converter's output voltage with constant amplitude and low total harmonic distortion. By adjusting the gain of waveform control circuit, it can regulate the current distribution among the parallel-connected power converters. The current feed-forward circuit separates the power converter's output current into the fundamental component and the harmonic component, and amplifies them by different gain. The amplified fundamental component acts as a fundamental resistor to suppress the circulating current among the parallel-connected power converters, and the amplified harmonic component acts as a harmonic damper for preventing from high frequency oscillation generated by the L-C filter.

Abstract: A solar electricity generating system includes a solar cell and a DC/AC converter coupled to the cell. The first proposed method includes the steps of: (a) adjusting an output current of the DC/AC converter; (b) sensing an output voltage variation of the solar cell; (c) adjusting the output current in a direction of the variation; and (d) repeating the steps (a) to (c). The second proposed method includes the steps of: (a) adjusting a DC output voltage of the solar cell; (b) sensing an output current amplitude variation of the DC/AC converter; (c) adjusting the output voltage in a direction of the variation; and (d) repeating the steps (a) to (c).

Abstract: A backup power supply system supplies power from a first ac power source in normal condition. Once the first ac power source is abnormal or failed, the system automatically turns off the first ac power source and turns on a second ac power source with null transfer time. When the first ac power source is normal, a dc/ac power inverter is controlled to supply an approximately null current that a mechanical switch is allowed to being closed and no circulating current is generated between the first ac power source and the dc/ac power inverter. Since the mechanical switch is successively closed, and it requires no switching operation, the backup power supply system can supply the backup power with a null transfer time.

Abstract: A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator is consisted of a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and the supplied current is approximated to be a sinusoidal waveform. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.

Abstract: A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator is consisted of a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and is adapted to provide with a serial-connected virtual harmonic damping. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.

Abstract: A bi-directional dc/dc power converter having a neutral terminal includes a first dc voltage terminal set and a second dc voltage terminal set. When the direction of power flow is from the first dc voltage terminal set to the second dc voltage terminal set, the Output voltage of power converter is the double of the input dc voltage. When the power flow direction is in reverse from the second dc voltage terminal set to the first dc voltage terminal set, the output voltage of power converter is half of the input dc voltage in this power flow direction.

Abstract: A DC/DC boost converter is consisted of an inductor, a power electronic switch, a control circuit, a first diode, a second diode and a capacitor. The power electronic switch is not operated if the input DC voltage is higher than the specified low reference DC voltage and it is regarded as the normal input DC voltage. If the input DC voltage is lower than the specified low reference DC voltage and this condition is regarded as the abnormal input DC voltage, the power electronic switch is controlled by pulse width modulation control and a dc voltage across the capacitor is created. Then, the output DC voltage is the summation of the input DC voltage and the capacitor voltage. Thus, the inventive DC/DC boost converter operates only when the input DC voltage is abnormal, thereby avoid additional power loss in the duration of normal input DC voltage.

Abstract: A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator is consisted of a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and is adapted to provide with a serial-connected virtual harmonic damping. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.

Abstract: A hybrid reactive power compensation device comprises a passive type reactive power compensator and an active type reactive power compensator serially connected thereto. The passive type reactive power compensator is an AC power capacitor adapted to provide the reactive power that reduces capacity of the active type reactive power compensator. The active type reactive power compensator is consisted of a power converter, a DC capacitor, a high-frequency ripple filter and a controller. The hybrid reactive power compensation device can supply a linearly adjustable reactive power within a predetermined range, and the supplied current is approximated to be a sinusoidal waveform. Therefore, it can avoid the destruction of AC power capacitor caused by the power resonance.