1948 results about "Soft switching" patented technology

A three stage power source for an electric arc welding process comprising an input stage having an AC input and a first DC output signal; a second stage in the form of an unregulated DC to DC converter having an input connected to the first DC output signal, a network of switches switched at a high frequency with a given duty cycle to convert the input into a first internal AC signal, an isolation transformer with a primary winding driven by the first internal high frequency AC signal and a secondary winding for creating a second internal high frequency AC signal and a rectifier to convert the second internal AC signal into a second DC output signal of the second stage, with a magnitude related to the duty cycle of the switches; and, a third stage to convert the second DC output signal to a welding output for welding wherein the input stage has a regulated DC to DC converter with a boost power switch having an active soft switching circuit.

A resonant, bi-directional, DC to DC voltage converter with loss-less (soft) switching having regulated output and capable of converting power between two, high-potential and low-potential DC voltage sources. The converter's semiconductor and magnetic components provide both, output regulation and soft switching in both (step-down and step-up) directions of power conversion which reduces total component count, cost and volume and enhances power conversion efficiency.

The invention provides a driving circuit and a driving method applied to a flyback-type converter and a quasi-resonant soft-switching flyback-type converter applying the same. According to a driving circuit applied to the flyback-type converter, differential coefficient of the drain-source voltage of a main power switch tube in the flyback-type converter is worked out by a differential circuit, thus leading the time when the drain-source voltage achieves valley floor to correspond to the time when the differential voltage passes the zero point in positive direction. A valley floor voltage detecting circuit is connected with the differential circuit and receives a differential voltage signal; when the drain-source voltage of the main power switch tube achieves the valley floor, a valley floor control signal is output, thus controlling the driving circuit to drive the main power switch tube, and further exactly realizing the aim of conducting the valley floor of the main power switch tube. By adopting the driving circuit, the aim of controlling a quasi-resonant soft switch of the main power switch tube is realized precisely, the driving circuit of the flyback-type converter is optimized so that the controlling effect and the reliability are greatly improved, and the realizing cost is reduced.

A method in wireless communication systems is provided for switching from P2P (Peer to Peer) communication mode to UP-UTRAN-DOWN (conventional communication mode) and from conventional communication mode to P2P mode, wherein the method performed by a user equipment for switching from P2P communication mode to conventional communication mode comprising steps of: detecting the direct link used by the user equipment in P2P communication with the other user equipment; sending a request for switching to conventional communication mode to a wireless communication network system if the detecting result indicates that the communication quality of the direct link can't satisfy the requirement for P2P communication; and establishing conventional communication connection so as to communicate with said the other user equipment in conventional mode, after receiving the acknowledge (ACK) message of the request for switching sent by the network system.

There is provided by this invention soft switching interleaved power converters that are suitable for high power and high voltage applications such as plasma processing. They have greatly reduced switching losses and diode reverse-recovery losses which allows operation at high switching frequencies. The peak values of the reverse-recovery currents of the diodes are substantially less then their peak forward operating currents. The power converters incorporate power converter cells that comprise a plurality of switching assemblies that are operated with an interleaved switching pattern, and that are each connected to an input terminal of an inductor assembly that also has a common terminal. The inductance between each pair of input terminals is less than the inductance between each input terminal and the common terminal of the inductor assembly.

The invention discloses an electric field coupling-based wireless power transmission system. The system comprises a power supply circuit, a high-frequency inverter circuit, a tuning circuit, an electric field coupling polar plate, a rectifier filter circuit and a load circuit and is characterized by also comprising a coupling capacitance detection module, a controller and a fixed frequency drive circuit; a capacitance compensation array is arranged in the tuning circuit; the controller detects parameters of the electric field coupling polar plate and controls compensation values of the capacitance compensation array through the coupling capacitance detection module, and outputs fixed frequency control signals; and the fixed frequency signals are transmitted to the fixed frequency drive circuit, and then the high-frequency inverter circuit is driven to work. The electric field coupling-based wireless power transmission system has the advantages that based on the electric field coupling, the transmission capacity and efficiency of the system are improved by adopting an E amplifier; and by arranging the coupling capacitance detection module, the electric field coupling polar plate of the system is detected in real time, and the capacitance compensation value can be effectively controlled, so that the system is kept in the soft switching state, and the power transmission stability and reliability of the system are improved.

A system comprises a primary switch network coupled to a power source, wherein the primary switch network comprises a plurality of power switches, a primary resonant tank coupled to the plurality of power switches, wherein a resonant capacitor of the primary resonant tank is formed by a first variable capacitance network, and wherein the first variable capacitance network is modulated to improve soft switching of the plurality of power switches through reducing a voltage level and a current level of a switch at a turn-on instant and a primary coil coupled to the primary resonant tank.

A power system for a dielectric barrier discharge system, such as used for generating ozone, can include a full bridge inverter stage and parallel resonant tank outputting a signal for powering a dielectric barrier discharge cell stack. The inverter stage is controlled using a combination of pulse width modulation (PWM) and frequency modulation (FM) to enable soft switching through all load conditions—from full load to light load. A current control loop error amplifier compensator can provide a duty cycle adjustment signal to a phase shift PWM controller chip that generates the switching signals for the inverter stage. A feedback signal is also used to adjust a clock frequency time constant of the PWM controller chip to provide the FM. In one embodiment, the feedback signal is an output of an inverting amplifier connected at an output of the current control loop error amplifier compensator.

A synchronous regulation circuit is provided. A secondary-side switching circuit is coupled to the output of the power converter to generate a synchronous signal and a pulse signal in response to an oscillation signal and a feedback signal. An isolation device transfers the synchronous signal from the secondary side to the primary side of the power converter. A primary-side switching circuit receives the synchronous signal to generate a switching signal for soft switching a transformer. The pulse signal is utilized to control a synchronous switch for rectifying and regulating the power converter. The synchronous switch includes a power switch and a control circuit. The control circuit receives the pulse signal for turning on or off the power switch. The power switch is connected between the transformer and the output of the power converter. A flyback switch is operated as a synchronous rectifier to freewheel the inductor current of the power converter. The flyback switch is turned on in response to the off state of the power switch. The turn-on period of flyback switch is correlated to the turn-on period of the power switch.

A video noise reduction system for a set of video frames that computes a first motion signal using a current frame and multiple consecutive previous frames, computes a second motion signal using the current frame and the processed preceding frame; computes the multi-frame temporal average of the current frame and multiple consecutive previous frames; computes the recursive average of the current frame and the processed preceding frame; generates a temporal filtered signal by soft switching between the multi-frame temporal average and the recursive average based on the first motion signal; applies a spatial filter to the current frame to generate a spatial filtered signal; and combines the temporal filtered signal and the spatial filtered signal based on the second motion signal to generate a final noise reduced video output signal.

The present invention is a circuit and method for reducing switching and reverse recovery losses in the output rectifiers while creating zero voltage switching conditions for the primary switchers. There are described two output configurations, one employing a soft commutation inductor element a bridge rectifier and a output filter capacitor, the second using a soft commutation inductor element a rectification-filtering bridge composed by two capacitors and two capacitors. Both secondary circuits can be driven by three primary circuits. A first circuit is a full bridge with phase shift control, and a second circuit is a half bridge topology with an additional bydirectional switch which achieves two goals, on to get soft switching commutation across all the primary switches, the second to create the right waveforms in the secondary suitable with the claims in this invention. The third topology is a phase shifted two transistors forward. The circuits claimed in this invention can provide soft commutation across the primary switching elements and secondary rectifier means, clamping the voltage across the rectifiers to the output voltage eliminating the need for snubbers circuits both in primary and the secondary section.

The present disclosure discloses a bi-directional DC-DC converter, comprising a primary-side inverting/rectifying module, an isolated transformer, and a secondary-side rectifying/inverting module, wherein the primary-side inverting/rectifying module comprises a first bridge arm composed of a first switching component and a second switching component connected in series and a clamping circuit comprising a resonant inductor and a clamping bridge arm composed of a first semiconductor component and a second semiconductor component connected in series, and two terminals of the resonant inductor are respectively coupled to a common node of the first switching component and the second switching component and a common node of the first semiconductor component and the second semiconductor component. The present disclosure can improve transformer efficiency while achieving the soft switching of the switching components.

A DC converter comprises a half bridge supply circuit and one or more flyback or forward converter output circuits, and optionally also an LLC converter whose control can determine a common variable switching frequency. The half bridge supply circuit produces a 50% duty output alternating between two input voltages, such as zero and a voltage Vin. In each flyback or forward converter output circuit, a switch connects a transformer primary to the half bridge supply circuit output in a PWM controlled manner to regulate a respective flyback or forward converter DC output which is produced by the converter output circuit, with a duty ratio less than 50% whereby switching losses are reduced. Soft switching is further facilitated by the half bridge supply circuit having two transistors controlled in a complementary manner.

The present invention relates to a soft switching DC-DC converter. A soft switching DC-DC converter comprises a first switching element having a first terminal connected to an input side and having a control terminal for controlling a main electric current; a first diode having a first terminal connected to a second terminal of this first switching element; a primary coil of a transformer having primary and secondary coils, connected to the second terminal of the first switching element; a second diode having a first terminal connected to the first terminal of the first switching element; a second switching element having a first terminal connected to the second terminal of this second diode; and the secondary coil of the transformer, having a first terminal connected to a second terminal of this second switching element, and having a second terminal connected to the second terminal of the first switching element. The soft switching DC-DC converter allows a substantial reduction of the loss in the capacitor operation, by including a resonant circuit composed of a transformer.

A synchronous regulation circuit is provided to improve the efficiency for an offline power converter. A secondary-side switching circuit is coupled to the output of the power converter to generate a synchronous signal and a pulse signal in response to an oscillation signal and a feedback signal. An isolation device transfers the synchronous signal from the secondary side to the primary side of the power converter. A primary-side switching circuit further receives the synchronous signal to generate a switching signal for soft switching a transformer. The pulse signal is utilized to control a synchronous switch for rectifying and regulating the power converter. The synchronous switch includes a power switch and a control circuit. The control circuit receives the pulse signal for turning on/off the power switch. The power switch is connected in between the transformer and the output of the power converter. In addition, a flyback switch is operated as a synchronous rectifier to freewheel the inductor current of the power converter. The flyback switch is turned on in response to the off of the power switch. The on time of flyback switch is correlated to the on time of the power switch.

A buck-boost switching converter includes a soft-switching circuit coupled across the boost switch, controlled to establish a short-circuit across the boost switch prior to turn-on of the boost switch. The converter also includes a second soft-switching circuit including a third switch and a saturable inductor coupled across the buck switch. The third switch is rendered conductive sufficiently before the buck switch so that a half-cycle of resonance can occur between the saturable inductor and the buck switch.

A resonant converter comprising: a controllable current source; a resonant tank circuit coupled to the current source; and an isolated buck-type converter coupled to the resonant tank circuit, the isolated buck-type converter having an output, wherein the resonant tank circuit enables switches in the isolated buck-type converter to switch under soft-switching conditions. In some embodiments, the controllable current source is a switch-mode-type current source. In some embodiments, the isolated buck-type converter comprises a half-bridge converter. In some embodiments, the isolated buck-type converter comprises a full-bridge converter. In some embodiments, the isolated buck-type converter comprises a push-pull converter.

A small and efficient DC-DC converter is provided. In this DC-DC converter, passive elements such as an inductor and a capacitor can be reduced in size by reducing switching loss by a soft switching technology and increasing the drive frequency of a switching element. The DC-DC converter has a main switching element, a main diode and an auxiliary circuit that discharges the electric charges of the capacitance between the ends of the main switching element. The DC-DC converter includes an auxiliary inductor magnetically coupled with the main inductor, an auxiliary switching element that stores energy in the auxiliary inductor, and an auxiliary diode that discharges energy stored in the auxiliary inductor to the direct-current power source or the output side. The auxiliary inductor is coupled with the main inductor in the direction in which backward voltage is applied to the auxiliary diode when the main inductor discharges energy.