83results about How to "Implement soft switching" patented technology

The invention provides an input-series-output-parallel auto balanced voltage transformer based on a full-bridge topology belonging to the dc transformer field. The dc transformer is composed of N dc transformers with a full-bridge topology structure (N is natural number), wherein the input ends of the dc transformer power modules are mutual in-series and connected to the positive and negative terminals of a dc voltage source, the output ends are mutual parallel and connected to two ends of an output filter capacitor. Each power module of the full-bridge topology structure dc transformer comprises an input capacitance, a full-bridge circuit, a series inductance, a high frequency isolating transformer and an output rectifier circuit. The full-bridge circuit comprises a full-bridge circuit formed by four switch tubes, each power module works in the same work frequency or a different work frequency at a duty cycle near to 0.5. The balance voltage at each input side of the power module is auto realized using the input-series-output-parallel structure and secondary side clamping action of the transformer. The transformer provided by the invention not only can be applied in the occasion that no voltage adjustment is needed during the input and output high voltage, but also the occasion of different input voltage grades, which has a good application flexibility and has certain application prospects in the high voltage input and high power occasions.

The invention relates to a photovoltaic high-frequency isolation boost soft switch DC/DC converter and a control method thereof, which is used for solving the problems of difficult current conversion of leading leg in idle load or light load and low efficiency in full load, improving the efficiency of the converter and realizing full-power converter. The photovoltaic high-frequency isolation boost soft switch DC/DC converter comprises a high-frequency transformer, wherein the primary side of the high-frequency transformer is provided with a phase shift PWM (pulse-width modulation) control converter; the high-frequency transformer is provided with three secondary sides; two secondary sides are formed by connecting bridge type diode rectification circuits in series for outputting high voltages, the output ends of the secondary sides are connected with output voltage and current sampling circuits, and the output voltage and current sampling circuits are connected with a controller; the third secondary side is formed by connecting a voltage dropping winding with a current converting inductor and a switch in series; the primary side of the transformer is provided with a blocking capacitor Cb and a saturation inductor LS which are connected in series; output filtering capacitors Lfl and Lf2 are coupling capacitors and share one magnetic core; output ends Df1-R1-Cf1 and Df2-R2-Cf2 form a crossed clamping buffer circuit; and the asymmetrical phase shift PWM controller controls power switching devices VT1 to VT4 and a switch K0.

The invention provides an LLC resonance type push-pull forward conversion topology. The topology is mainly characterized in that: on the basis of a current push-pull forward conversion topology, an L resonance circuit and a C resonance circuit are added at a secondary rectifier side. The topology uses the L resonance circuit and the C resonance circuit at a transformer secondary to eliminate a turn-off peak on a secondary rectifier diode; therefore, an RC absorption circuit or a CDD absorption circuit in an original push-pull forward conversion topology circuit can be removed, wherein the RC absorption circuit or the CDD absorption circuit is arranged for a diode backward recovery peak; and a filter inductor that is arranged at the back of the rectifier diode can also be removed. Meanwhile, soft switching of a main power tube can be realized; an EMC effect based on a topological converter can be improved; and losses of a main power switch tube and the rectifier diode can be reduced. Besides, the topology can be applied to a preceding stage of an inverter. According to the invention, the LLC resonance type push-pull forward conversion topology has advantages of simple structure, convenience, and reliable working and the like; and advantages like soft switching of various power devices and the like can be realized; therefore, the topology has a certain practical value.

The invention discloses a bidirectional resonance DC converter and a control method thereof. The bidirectional resonance DC converter is formed by a low-voltage side power supply, a high-voltage side power supply, low-voltage side first switch tube-low-voltage side fourth switch tube, high-voltage side first switch tube-high-voltage side fourth switch tube, first and second resonant inductors, a resonant capacitor, first and second capacitors and a transformer. When energy is transmitted from the lower voltage side to the high voltage side, the bidirectional resonance DC converter realizes power control through phase-shifting control of the switch tubes at the two sides; and when the energy is transmitted from the high voltage side to the low voltage side, the bidirectional resonance DC converter realizes power control through frequency converting control of the switch tubes. The bidirectional resonance DC converter not only can realize bidirectional transmission and control of the energy at the two sides, but also can realize soft switching of all switch devices in full load range, and is especially suitable for being applied to high-frequency, high-efficiency and high-power-density two-way power transformation occasions.

The invention discloses a control type soft-switching technology for an inverter, and belongs to the field of power electronic converters. The control type soft-switching technology for the inverter is suitable for the traditional full-bridge inverter topology with low power and the traditional half-bridge inverter topology with low power. According to the soft-switching technology, a zero voltage switch environment of a switch device is built by controlling the positive direction, the negative direction and the reverse direction of the output inductive current in one cycle. For the three modulation modes of the inductive current, a digital-analog hybrid control circuit and method which are simple and easy to implement are provided. The control type soft-switching technology for the inverter has the advantages of being high in efficiency, small in size of a passive element, low in cost and the like and is especially suitable for small-power application occasions.

The invention proposes a novel AC power electronic transformer topological structure. According to different application occasions, the AC power electronic transformer topological structure proposed by the invention can be divided to two types and comprises a novel power electronic traction transformer topological structure applied to a high-speed train traction transmission system and a novel three-phase AC power electronic transformer topological structure applied to an interconnection three-phase middle/high-voltage AC power grid and a low-voltage DC power grid. With the basic topological structure proposed by the invention, an arbitrary fault converter in a DC/DC conversion unit can be automatically removed, and a DC bypass contactor is not needed to be employed; and on the basis of abasic topological structure, a bidirectional isolation DC/DC converter can be arbitrarily reduced while the bidirectional isolation DC/DC converter in at least one group of DC/DC conversion unit is maintained by sharing half-bridge arm of a voltage sharing converter and a cascaded isolation DC/DC converter, so that the numbers of middle/high-frequency transformers and low-voltage switch devices can be reduced, and the volume, the weight and the cost of the AC power electronic transformer are further reduced.

The invention relates to a non-contact power supply primary circuit with a current expanding function. The non-contact power supply primary circuit comprises an inverter and a primary coil, wherein a primary compensating circuit is connected between the inverter and the primary coil. The primary compensating circuit comprises a first inductor, a first capacitor and a second inductor, wherein one end of the first inductor is connected with the output anode end of the inverter, the other end of the first inductor is connected with one end of the first capacitor and a first end of the second inductor, a second end of the second inductor is connected with one end of the compensating circuit through the primary coil, and the other end of the compensating circuit is connected with the other end of the first capacitor and the output cathode end of the inverter. The compensating circuit compensates inductance in the primary coil, and a resonance circuit is formed between the compensating circuit and the primary coil to enable the first inductor, the first capacitor and the second inductor to form the circuit with the current expanding function. The non-contact power supply primary circuit with the current expanding function can achieve constant control of currents of primary cables, has the current expanding function and is wide in application range and safe and reliable.

The invention discloses a modulation method of a three-phase isolation type bidirectional direct-current converter under double PWM (pulse width modulation). The modulation method includes steps of 1) determining seven switch modes by adopting a PWM strategy according to the conditions that phase shift angle and duty ratio of corresponding drive signals on two sides of a three-phase transformer change to generate different voltage and current waveforms on two sides of the transformer; 2) calculating soft switching ranges corresponding to the switch modes; 3) calculating minimum current peak flowing through the three-phase transformer within the soft switching range of each switch mode; 4) comparing calculation results to obtain the situation that the current peak flowing through the three-phase transformer is minimum on the premise of soft switching within the integral power range; 5) giving output power and voltage transmission ratio and determining the switch modes and corresponding the duty ratio and the phase shift angle by judging the range where the output power and the voltage transmission ratio belong to. On the basis of soft switching, the current peak is minimum, switch loss of switching devices is reduced and efficiency of the converter is improved.

The invention discloses a PFC soft switching circuit of a BOOST circuit. The PFC soft switching circuit comprises a switch SW4 and a freewheel diode D1 in the BOOST circuit, and also comprises an inductor L2, a capacitor C1, a capacitor C2, a diode D2, a diode D3 and a diode D4, wherein a branch formed by the capacitor C1 and the diode D2 homodromously connected in series is homodromously connected with the two ends of the freewheel diode D1 in parallel; the PFC soft switching circuit also comprises a freewheel diode D5, a switch SW1, an inductor L3, an inductor L4, a diode D5, a diode D7, a diode D8, a capacitor C4, a capacitor C5, a capacitor C6 and a resistor R6, wherein the negative pole of an input power VCC is connected with one end of the inductor L4, and the other end of the inductor L4 is connected with the cathode of the freewheel diode D5. The PFC soft switching circuit does not need the complex control technology, nor need the auxiliary IGBT, is simple and effective in implementation mode, and can always achieve useful effect from light load to heavy load.

The invention discloses an electric automobile charger. An uncontrolled rectifier and a BUCK type PFC two-stage structure are adopted in a main circuit, the charger is of a two-channel parallel structure, the power level of a convertor is improved, the heat distribution of the system is improved, the reliability of the system is improved, the service life of the system is prolonged, power factors of the system are greatly improved, and the power factors reach 0.998 in the stable status. A ZCS resonance circuit is adopted in the charger, soft switching of a switching element is achieved by controlling the matching of the communicating time of a Q1 and a Q4 and the resonant periods of a Cr and an Lr, and therefore the efficiency of the convertor is greatly improved. A switching tube Q2 and a switching tube Q3, and a switching tube Q5 and a switching tube Q6 form two bridge arms of an inverter circuit respectively, full-control type inversion is carried out by controlling communication signals of the switching tubes, and a single-phase alternating-current portable power source is provided. The requirements of the automobile charger for being small in size, light in weight and low in cost are met through the effective reuse of hardware.

The invention belongs to the technical field of medical electronics, and particularly relates to a radio frequency adjustable phase difference power amplifier circuit realizing linear ablation. The structure of the circuit comprises a phase control unit, a radio frequency amplitude control unit, a radio frequency resonance and filtering circuit, and an impedance matching network. Due to adoption of the impedance matching network, changing myocardial impedance in ablation is equivalent within a rated load range of the circuit, so that the circuit interior loss is reduced, and output frequency is stabilized; due to adoption of a soft-switching technology, zero voltage opening or zero voltage derivative opening of an electronic switching tube is realized, so that switching loss is lowered, and the working efficiency is improved. Through adoption of the circuit, the defect that continuous ablation lesions are hard to form in a conventional point-by-point dispersing radio frequency ablation technology is overcome, and continuous linear ablation effect is produced through adjustment of phase difference of radio frequency output voltages of adjacent ablation electrodes, so that continuous linear ablation of myocardial tissue is realized.

The invention discloses a high-power high-frequency switching power supply module and a device. The high-power high-frequency switching power supply module comprises an alternating-current input port,a rectifier bridge module, a power factor correction circuit, an LC filter circuit, at least one high-frequency DC/DC conversion module, an output filter capacitor, an output current sensor, a direct-current output port and a control module. The high-frequency DC/DC conversion module is composed of a high-frequency inverter bridge, a resonant inductor, a resonant capacitor, a high-frequency transformer, a high-frequency rectifying circuit, a high-frequency filtering capacitor and a current transformer. The input ends of N high-frequency DC/DC conversion modules are connected in parallel, andthe output ends of N high-frequency DC/DC conversion modules are connected in series or in parallel. The power supply module is simple in overall structure, can achieve high-power, low-ripple and low-load effect output, and can solve the technical problems that some equipment power supplies cannot meet the requirements of high power, high efficiency, high power factor, high power density, low output ripple, and being easy to replace and maintain at the same time.

The invention discloses a bidirectional three-port non-isolated DC converter and a control method thereof and belongs to the technical filed of a power electronic converter. The bidirectional three-port non-isolated DC converter is formed by four switch tubes, one coupling inductor comprising a first winding and a second winding, one high-frequency inductor and an auxiliary capacitor. The bidirectional three-port non-isolated DC converter can be connected with three power supplies of a low-voltage side power supply, a middle side power supply and a high-voltage side power supply and the like simultaneously, and can realize single stage and bidirectional power conversion between any two power supplies. Duty ratio and phase shift control are adopted simultaneously to provide two independent control variables for the system, so that any two ports can be in a controlled state simultaneously, and soft switching of all switch tubes can be realized. The bidirectional three-port non-isolated DC converter has the advantages of simple structure and control, high power density, high efficiency and low cost and the like, and is very suitable for the power systems of hybrid energy storage, electric automobile and DC microgrid and the like, which comprise a plurality of energy storage or a plurality of bidirectional DC buses.

The invention discloses a multi-resonant-cavity LLC resonant converter, which comprises a primary side switching network, a main resonant cavity RC1, auxiliary resonant cavities RC2 and RC3, auxiliaryresonant cavity switched-in switched-out switching tubes S5 and S6, a corresponding rectifying circuit FR1 when the main resonant cavity RC1 works, and a corresponding rectifying circuit FR2 when theauxiliary resonant cavities RC2 and RC3 work. According to the invention, the circuit can be in different working modes, i.e., a high-voltage output working mode, a medium-voltage output working modeand a low-voltage output working mode, by switching the resonant cavities in which the circuit actually works, and the gain ranges in the three working modes are continuous, so that the circuit obtains a wide output gain; and meanwhile, under the three working modes, the circuit can achieve the required output gain in a rated working frequency range by adopting a frequency conversion control mode, so that soft switching of the switching tubes in a full output gain range is ensured, relatively large ring current is avoided, and relatively high working efficiency of the circuit in the full output gain range is ensured.

The invention discloses an active clamping LED driving power supply without an electrolytic capacitor. The active clamping LED driving power supply comprises an AC input power supply, an input filtering part, a rectification part, a clamping circuit, a flyback converter, an output filtering capacitor Co, a parallel absorption loop and an LED load. The input filtering part is composed of an input filtering inductor and an input filtering capacitor. The rectification part is composed of four switch tubes. The clamping circuit is composed of a switching tube S2 and a clamping capacitor Caux; theflyback converter is composed of a flyback transformer, a switching tube S1 and a diode Ds. The flyback transformer comprises a primary side winding and a secondary side winding, the primary side winding comprises a main inductor Lm and a leakage inductor Lr, the primary side winding is connected with the input, and the secondary side winding is connected with the output; the parallel absorption circuit comprises a boost inductor Lb, a switching tube S3, a switching tube S4 and an energy storage capacitor Cds. According to the invention, the active clamping circuit is introduced, so that the switching stress of the switching tube S1 is reduced; both the switching tube S1 and the switching tube S2 realize soft switching, so that the switching loss is reduced; meanwhile, leakage inductance energy can be fed back.

A soft switching current-fed push-pull DC/DC converter includes a DC power source Uin, a flyback transformer TX1, a main transformer TX2, a fourth diode D4 connected to a secondary winding of the flyback transformer TX1, an output capacitor Co and a load resistor R0. The soft switching current-fed push-pull DC/DC converter further comprises a primary side circuit connected to the primary windingsof the two transformers and a rectifier circuit connected to the secondary winding of the main transformer. The converter adds a serial first power switch tube on the primary circuit connected with the two transformers and assist in a corresponding switching timing sequence to achieve soft switch switching of the switch tube. The soft switch switching of the switch tube is achieved, the switchingloss is reduced, and the working efficiency is improved.

The invention provides a high-frequency power source of a resonant coupling type wireless power transmission device. The high-frequency power source is formed by a switching tube, a snubber capacitor, a transmitting coil, a tuning capacitor and an energy storage filter inductor, high-frequency sine alternating currents can be output, soft switching of the switching tube can be achieved, and efficiency of the high-frequency power source is improved. The high-frequency power source is simple in structure and low in cost and is provided with a small number of elements, and the loss is close to zero, so that the high-frequency power source is very suitable for serving as an alternating current excitation source of a transmitting coil of the wireless power transmission device.

The invention discloses an isolated bridge type three-port DC converter which comprises an inversion unit, an isolation unit, a first output unit and a second output unit, the port at one side of the inversion unit is used for connecting a renewable energy source, the port at the other side of the inversion unit is connected with the isolation unit, the port at one side of the first output unit is connected with the isolation unit, the port at the other side of the first output unit is used for connecting a load, the port at one side of the second output unit is connected with the isolation unit, the port at the other side of the second output unit is used for connecting an energy storage device, the isolation unit is formed by two three-winding transformers, primary-side windings of the two three-winding transformers are connected in series, secondary-side windings of the two three-winding transformers are crossed in a group way and inversely and mutually connected in series, therefore, an output port and the energy storage device share complementary pulse, circulation among the renewable energy source, the energy storage device and the load is eliminated, and energy loss brought by the circulation is reduced.