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 fails, 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 such that a mechanical switch is allowed to be closed and no circulating current is generated between the first ac power source and the dc/ac power inverter. Since the mechanical switch is continuously closed, and requires no switching operation, the backup power supply system can supply the backup power with a null transfer time.

Abstract: A bidirectional active power conditioner includes a DC side, a bidirectional DC/DC power converter, a DC/AC inverter and an AC side. The DC side electrically connects with a DC source while the AC side electrically connects with a load and an AC source. The bidirectional DC/DC power converter is controlled via high-frequency pulse width modulation (PWM) switching so as to generate a predetermined DC voltage or DC current while the DC/AC inverter is controlled to convert the predetermined DC voltage or DC current into a predetermined AC voltage or AC current.

Abstract: A maximum power point tracking method, applied to a tracking device, employs a DC/DC converter connecting with a solar cell array, and including a controller actuating the DC/DC converter to perform an active resistance characteristic; a maximum power point tracking circuit adjusting the active resistance of the DC/DC converter; monitoring a change of an output power of the solar cell array in determining a direction for adjusting the active resistance of the DC/DC converter; and the maximum power point tracking circuit repeatedly adjusting the active resistance of the DC/DC converter. If the change of the output power of the solar cell array is positive, the active resistance of the DC/DC converter is adjusted in the same direction; but, conversely, if the change of the output power of the solar cell array is negative, the active resistance of the DC/DC converter is adjusted in an opposite direction.

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 diagnosis method for SOH of batteries includes the steps of: providing data of discharge voltages and currents of a battery unit; setting an acceptable value of a predetermined period of time and an acceptable range of variation rate of discharge current for the battery unit; calculating variation rates of discharge voltages and currents of the battery unit within the predetermined period of time by using the data of discharge voltages and currents; recording the data of discharge voltages and currents of the batteries and variation rates thereof; comparing the data of discharge voltages of the batteries and the variation rates thereof if the variation rates of discharge current are fallen within the acceptable range of current variation with selected reference data; and converting results of compared data of discharge voltages of the battery unit and the variation rates thereof into a SOH index.

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 structural configuration that reduces the number of power electronic switches, which can reduce manufacturing costs.

Abstract: An improved method of controlling build-up of adhesive coating on a Yankee drying cylinder preferably includes intermittently: (a) increasing the add-on rate of resinous adhesive to the drying cylinder substantially above the steady-state add-on rate; (b) segregating the absorbent sheet product produced while the add-on rate of resinous adhesive to the drying cylinder is elevated above the steady-state add-on rate from absorbent sheet product accumulated during steady-state operation; and (c) while the add-on rate of resinous adhesive to the drying cylinder is increased above the steady-state add-on rate, stripping at least a portion of the adhesive coating from the drying cylinder with a cleaning doctor.

Abstract: An islanding detection apparatus for a distributed generation power system and a detection method therefor operates a power converter to act as a virtual capacitor or inductor at a frequency close to but unequal to that of a utility power system under abnormal condition of the utility power system. When power failure occurs in the utility power system, only the distributed generation power system supplies power to a load so that a load voltage has been changed in at least one of amplitude and frequency which can be immediately detected islanding phenomenon.

Abstract: An active power conditioner, connecting with a load and a power source in parallel, includes a DC power capacitor, a power converter, a high-frequency filter and a control circuit. The control circuit detects the voltage of the DC power capacitor and the current of the power source, thereby performing a closed loop control to stabilize the voltage of the DC power capacitor and performing a feed forward control to generate a driving signal for driving the power converter. The power converter actuates the DC power capacitor to supply a current via the high-frequency filter to reduce the reactive and harmonic components of load current. The load is converted to the linear resistance characteristic, observed from the power source side.

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: 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 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 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 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.