A power converter includes a converter, a smoothing capacitor, an inverter, and a controller. The converter rectifies a power supply voltage applied from an alternating-current power supply. The smoothing capacitor smooths a rectified voltage output from the converter into a direct-current voltage including a ripple. The inverter converts the direct-current voltage smoothed by the smoothing capacitor into an alternating-current voltage to be applied to a motor. The controller performs control such that a first physical quantity representing an operation state of the converter is equal to a second physical quantity representing an operation state of the inverter.

A motor drive that outputs a sinusoidal waveform utilizes power switching devices operable at high switching frequencies. The switching devices may be operated, for example, between twenty kilohertz and one megahertz. A first filter is included at the output of the motor drive which has a bandwidth selected to attenuate voltage components at the output which are at the switching frequency or multiples thereof such that the output voltage waveform is generally sinusoidal. Additional filtering is included within the motor drive to establish a circulation path for common mode currents within the motor drive. Further, a shield is provided adjacent to those components within the motor drive that may experience voltage or current waveforms at the switching frequency or multiples thereof to cause radiated emissions to establish eddy currents within the EMI shield rather than passing through the shield into the environment.

A line commutated converter (LCC) for a high voltage direct current power converter, the LCC comprising at least one LCC bridge circuit for connection to at least one terminal of a DC system, each bridge circuit comprising a plurality of arms, each associated with a respective phase of an AC system, each arm comprising: an upper thyristor valve or valves, and lower thyristor valve or valves connected in series; an associated branch extending from between the upper and lower thyristors; and at least one thyristor-based capacitor module for each phase, each module comprising a plurality of module thyristors, the or each capacitor module operable to insert a main capacitor into the respective arm of the bridge circuit by firing at least one or more of said module thyristors.

A capacitive power supply circuit including, between first and second terminals of application of an AC input voltage-UN, a distributed capacitive structure including a plurality of elementary capacitive units, each including a current limiter series-connected with a capacitor between first and second terminals of the unit and a voltage limiter connected in parallel with the capacitor, the elementary capacitive units being series-coupled by their first and second terminals.

A power converter including: a first branch and a second branch of at least two series-connected switches each, coupled in parallel between a first terminal and a second terminal and having the junction points of their switches coupled to two terminals of application of a first voltage; a third branch and a fourth branch of at least two series-connected switches each, coupled in parallel between a third terminal and a fourth terminal, and having the junction points of their switches coupled to two terminals for supplying a second voltage; and at least one piezoelectric element coupling the first terminal to the third terminal.

A high voltage rectifier includes: a power divider (2) dividing power of high-frequency wave RF to be rectified; a capacitor (3) cutting-off direct current flowing between the power divider (2) and a first rectifier (10): and a capacitor (4) cutting-off direct current flowing between the power divider (2) and a second rectifier (20). The first rectifier (10) generates a direct-current voltage DC.sub.1 by rectifying a high-frequency wave RF.sub.1 output from the power divider (2), and outputs the direct-current voltage DC.sub.1 to one end of a load (7). The second rectifier (20) generates a direct-current voltage DC.sub.2 having a different polarity from that of the direct-current voltage DC.sub.1 by rectifying high-frequency wave RF.sub.2 output from the power divider (2), and outputs the direct-current voltage DC.sub.2 to the other end of the load (7).

A wireless power transmission system has a wireless power receiving device that can be charged using multiple different types of wireless power transmitting devices. The different types of wireless power transmitting devices have power transmitting coils that exhibit different levels of magnetic coupling with the power receiving coil of the wireless power receiving device. The wireless power receiving device may include capacitors, resistors, and/or other loading circuits that can be independently switched into use depending on the level of magnetic coupling that is detected, on a rectified voltage level, on the size of the output load, and/or on information conveyed during handshaking operations to present a desired impedance adjustment at the power receiving coil so that data signal can be properly conveyed between the power receiving device and the power transmitting device.

A capacitor-drop power supply includes a rectifier and a switched capacitor converter coupled to the rectifier. The rectifier is configured to receive an alternating current (AC) signal at an AC voltage and convert the AC signal into a rectified direct current (DC) signal at a rectified voltage. The switched capacitor converter is configured to receive the rectified DC signal and generate a converter output signal at a converter voltage that is proportional to the rectified voltage and that is less than the AC voltage.

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.

A power supply includes an active bridge section with input terminals that receive power from a constant current source where the active bridge section operates at a fixed switching frequency. The power supply includes a resonant section with a resonant inductor and a resonant capacitor. The resonant section is connected to an output of the active bridge section. The power supply includes an output rectifier that receives power from the resonant section and includes output terminals for connection to a load and a controller that regulates output current to the load where the controller regulates output current to the load by controlling switching of the active bridge section. The fixed switching frequency of the active bridge section matches a resonant frequency of the resonant section.