A method for controlling a totem-pole PFC circuit. When an alternating current of an input end of a totem-pole PFC circuit is in a positive half period, if a previous switching period is less than specified duration, after charging of a PFC inductor is completed, a switch that enables the PFC inductor to be discharged is first delayed for specified threshold duration, and then the switch that enables the PFC inductor to be discharged is turned on, so that the switch that enables the PFC inductor to be discharged is turned on only once. In an existing PFC application, when an input voltage is in a positive half period, a switch that enables a PFC inductor to be discharged needs to be turned on twice.

The present invention discloses a lighting installation having an LED lamp (19), normally consisting of a series string of individual LED's (18), which is supplied by a rectifier (20, 200). A control circuit (23, 23 & C1) is interposed between the rectifier and the AC supply which powers the rectifier. Various circuits for filtering, power factor control, multi-phase operation and dimming, for example by phase switching, are disclosed. In particular, the control carried out by the control circuit takes place on the AC side of the rectifier. Also disclosed are the control circuit per se and a method of converting a High Intensity Discharge (HID) lamp installation into a Light Emitting Diode (LED) installation. The control circuit can take the form of an inductor, an inductor and series capacitor, a shunt inductor, a leakage reactance transformer, a constant current transformer, an autotransformer, an isolation transformer or a ferro-resonant transformer.

The disclosure relates to a method for reducing the torque ripple and noise evolution in an EC motor with single-phase feed by buffer-storing electrical energy in the EC motor, which is embodied with a power factor correction circuit (PFC) having a capacitor (Cz) at the power supply system input for a specific power supply system AC voltage UN, wherein the capacitance of the capacitor is dimensioned such that when the power supply system AC voltage UN is applied, a pulsating DC voltage is generated in a link circuit (Z), wherein the pulsating electrical energy generated as a result is stored by means of a primary regulation of the id current component as magnetic energy in the EC motor at least for a predefined time period.

A power controller for use in a PFC power converter is capable being immune from audible noise during the test of load transient response. A transconductor with a transconductance compares an output voltage of the PFC power converter with a target voltage to provide a compensation current, which builds up a compensation voltage. An ON-time controller is configured to end an ON time of a power switch in response to the compensation voltage. An OFF-time controller is configured to end an OFF time of the power switch. A compensation-voltage designator presets the compensation voltage. A status detector controls the transconductor, the ON-time controller, the OFF-time controller, and the compensation-voltage designator, in response to the output voltage, a top-boundary voltage and a bottom-boundary voltage.

An AC/DC converter and conversion method are provided, in which an AC input is rectified and shaped by a waveform shaping capacitor. A current source circuit is used to provide the output current to the output load which has a parallel bulk capacitor. The current source circuit is switched on and off with timing which is dependent on the phase of the AC input signal. This enables a relatively high power factor, for example between 0.7 and 0.9, with low cost circuitry with few components.

A control method of a PFC (Power Factor Correction) circuit having at least one power switch, the control method having: producing an effective value of an input voltage; generating a compensation signal based on an output voltage and an output voltage reference signal; generating an on time signal based on the compensation signal, the effective value of the input voltage, a first on time period value and a second on time period value; generating an on time delay signal based on the input voltage, the output voltage, the first on time period value, the effective value of the input voltage and the compensation signal; and generating a current valley signal based on the input voltage, the effective value of the input voltage, the compensation signal, the second on time period value, and an inductance value of the inductor adopted by the PFC circuit.

A UPS comprising an input, an output, a battery circuit, a PFC stage, a switch configured to selectively couple an interface of the PFC stage to the input in an online mode and to the battery circuit in a backup mode, a positive DC bus, a negative DC bus, and a controller configured to operate, in the online mode, the PFC stage to provide DC power, derived from the input AC power, to the DC busses, to operate, in the backup mode, the PFC stage to provide DC power, derived from the backup DC power, to the DC busses, to operate, in a first stage of the backup mode, the battery circuit to couple a positive terminal of a DC source to the interface, and to operate, in a second stage of the backup mode, the battery circuit to couple a negative terminal of the DC source to the interface.

A multi-phase shift transformer based AC-DC converter includes a single transformer that reflects a negative portion of an AC voltage to become a positive voltage by generating multiple phases from a poly-phase input. The multiple phases generated can be separated by as little as 1 to create a well-approximated DC output without the need for a smoothing circuit. The primary and second windings of the transformer are flat wire conductors structured to provide a larger number of windings per core including a larger number of secondary coils, which provides for a large number of output phases.

An electric power supply includes a totem pole bridgeless PFC power converter. The PFC power converter includes an input for coupling to an AC power source, an output, four switching devices coupled between the input and the output, two diodes coupled between the four switching devices and the input, a first inductor coupled between the four switching devices and the two diodes, and a second inductor coupled between the two diodes and the input. Other example electric power supplies and totem pole bridgeless PFC power converters are also disclosed.

A power supply device includes a PF correction circuit, a power switching circuit and a control circuit. The PF correction circuit converts an input voltage to a bus voltage according to a control signal to supply a later stage circuit. The power switching circuit selectively switches to conduct a first source or a second source to the PF correction circuit to provide the input voltage to the PF correction circuit. The control circuit outputs the control signal to the PF correction circuit. When the control circuit detects a first voltage of the first source connecting to the PF correction circuit is abnormal, the control circuit determines whether a second voltage of the second source is smaller than the bus voltage and controls the power switching circuit to switch when the second voltage is smaller than the bus voltage to conduct the second source to the PF correction circuit.