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148results about How to "Reduce switching losses" patented technology

Control method for auxiliary switching tube of active clamp flyback converter

The invention relates to a control method for an auxiliary switching tube of an active clamp flyback converter. In the flyback converter, severe energy loss and voltage spike of a main switching tube are caused due to leakage inductance of a transformer and leakage inductance of circuits. The conventional solution mainly comprises methods for solving the problems by using residual current device (RCD) clamp, liquid crystal display (LCD) clamp and active clamp, wherein an active clamp circuit can effectively recover leakage inductance energy and obviously improve the efficiency. The invention provides a novel control method on the basis of the conventional active clamp flyback converter topology. In the conventional control method, a primary side switching tube is in complementary conduction with an auxiliary switching tube in each period; and in the control method, the primary side switching tube is switched on in each period, the auxiliary switching tube is controlled by setting voltage of a clamp capacitor in the clamp circuit, and when the voltage of the clamp capacitor reaches the set value, the auxiliary switching tube is switched on. Compared with the prior art, the method has the advantages that: the switching loss of the auxiliary switching tube can be reduced; and more importantly, the efficiency of the circuit can be greatly improved under a light load, and the no-load loss is reduced.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Magnet isolation drive circuit

The invention relates to a magnet isolation drive circuit which is applied to a power switch tube of a power supply switch, in particular to the magnet isolation drive circuit which is applied to a silicon carbide power metal oxide semiconductor (MOS) tube. The magnet isolation drive circuit comprises a control circuit, a first capacity C1, an isolation driver transformer T1, a second capacity C2, a light emitting diode D1, a drive pulse amplifying circuit which is connected to the light emitting diode D1 in parallel, a voltage-regulator tube ZD1, a capacity C3 which is connected to the voltage-regulator tube ZD1 in parallel, a resistance R1 and a drive resistance Rg. The magnet isolation drive circuit effectively avoids leakage inductance of a side edge of a transformer T1 on a switch tube, reduces a drive voltage peak value, reduces possibility of breaking down the switch tube, is high in current driving capacity and improves switching frequency of the switch tube. A drive pulse possesses a negative voltage, is capable of effectively preventing from being misled by the drive switch tube and improves work stability of a power supply. The magnet isolation drive circuit is suitable for various duty ratio signals, is simple in structure and low in cost and is particularly capable of fully expressing a performance advantage of the silicon carbide MOS tube.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Tri-level zero-current conversion soft switching inverter of active middle voltage clamp

The invention relates to the field of electric and electronic inverter, and discloses a tri-level zero-current conversion soft switching inverter of active middle voltage clamp. The invention comprises a DC side positive pole, a DC side negative pole and a zero level; a first filtering capacitor is connected between the DC side positive pole and the zero level, and a second filtering capacitor isconnected between the negative pole and the zero level; each phase bridge arm comprises a first switching element, a second switching element, a third switching element, a fourth switching element, afifth switching element and a sixth switching element, wherein the first, the second, the third and the fourth elements are sequentially connected in series, the fifth switching element is connected between the shared node of the first and the second switching elements and the zero level, and the sixth switching element is connected between the of the third and the fourth switching elements and the zero level. The invention is characterized in that auxiliary switching elements and auxiliary diodes are connected between the shared node of the first and second switching elements and the shared node of the third and the fourth switching elements to form an auxiliary series connection circuit; a resonant capacitor and a resonant inductor which are sequentially connected in series are connectedbetween the shared node of the auxiliary switching elements and auxiliary diodes and the shared node of the second and the third switching elements.
Owner:XI AN JIAOTONG UNIV

Harmonic current fractional frequency staggered compensation device and harmonic current fractional frequency giving algorithm thereof

The invention discloses a harmonic current fractional frequency staggered compensation device and a harmonic current fractional frequency giving algorithm thereof. An active part of a main circuit of the device consists of a low-switching-frequency high-power inverter circuit unit and a high-switching-frequency low-power inverter circuit unit, wherein the low-switching-frequency high-power inverter circuit unit and the high-switching-frequency low-power inverter circuit unit are respectively responsible for generating low-frequency components and high-frequency components in harmonic reference current. The two inverter circuit units of the harmonic current compensation device share the same direct-current bus capacitor Cdc, and alternating-current sides of the two inverter circuit units are respectively and serially connected with a seventh serial harmonic branch circuit and a thirteenth serial harmonic branch circuit, then are connected with a filter capacitor and finally are connected to a power grid. A passive part formed by the serial harmonic branch circuits greatly reduces the power level of the active part. The separate giving of the reference current low-frequency components and high-frequency components is realized by adopting the harmonic current fractional frequency giving algorithm based on sliding DFT (Discrete Fourier Transform). The device effectively solves the contradictory constraint relationship among the active part components, the efficiency, the switching frequency and the compensation performance of the harmonic compensation device.
Owner:INNER MONGOLIA UNIV FOR THE NATITIES

Wind power generation system based on reverse loose matrix converter and method thereof

The invention discloses a wind power generation system based on a reverse loose matrix converter and a method thereof, and the structure of the wind power generation system based on the reverse loose matrix converter is as follows: the alternating current side of a rectifier stage is connected with a power grid, the direct current side of the rectifier stage is in butt joint with the direct current side of an inverter stage, the alternating current side of the inverter stage is connected with the output end of a permanent magnet synchronous generator, and the permanent magnet synchronous generator is connected with a fan; the input side of an active protection circuit is connected with the direct current side of an inverter, and the output side of the active protection circuit is connected with the alternating current side of the rectifier stage; the rectifier stage is a three-phase rectifier stage formed by six power device components, and each power device component is formed by connecting a controllable semiconductor power switch with a power diode in series; and the inverter stage is a three-phase bridge type inverter formed by six IGBTs (insulated gate bipolar transistors). The wind power generation system based on the reverse loose matrix converter can convert and transmit energy in a green, high-efficient and reliable manner, and simultaneously ensure the simple and compact structure and the low cost of the system.
Owner:CENT SOUTH UNIV

Single-phase PWM rectifier for railway AC/DC/AC standby power supply

The invention discloses a single-phase PWM rectifier for a railway AC/DC/AC standby power supply. The single-phase PWM rectifier comprises network voltages and an input filter unit which is electrically connected with the network voltages. The network voltages are electrically connected with a rectification unit through the input filter unit. The rectification unit is electrically connected with a DC voltage supporting unit connected with a load. The rectification unit comprises two switch power machines which are connected in series. The two switch power machines which are connected in series are connected in parallel with the input filter unit. The DC voltage supporting unit comprises two sets of positive voltage capacitors which are connected in parallel and then are connected in series. The two sets of positive voltage capacitors are connected in parallel to the rectification unit. A novel single-phase PWM rectifier topological structure is provided, and under the situation that a middle point control algorithm is not added into an inversion side, DC bus middle point potential balance can still be kept. In addition, the structure has the advantages of being simple, reliable, low in switch loss, high in power factor and stable in DC voltage, and idle exchanging is lowered.
Owner:QINGDAO VECCON ELECTRIC

Phase-shift full-bridge converter circuit and control method

The invention discloses a phase-shift full-bridge converter circuit which comprises a transformer, a lead bridge arm, a lag bridge arm and an output circuit. The lead bridge arm is formed by serially connecting a first MOS tube and a second MOS tube, the connection point of the two MOS tubes is sequentially connected with one end of a primary side of the transformer through a capacitor and a resonant inductor, and the capacitor and the resonant inductor are connected in series. The lag bridge arm is formed by serially connecting a third MOS tube and a fourth MOS tube, the connection point of the two MOS tubes is connected with the other end of the primary side of the transformer, and input direct-current voltage is applied to the positions between the connection point of the first MOS tube and the second MOS tube and the connection point of the third MOS tube and the fourth MOS tube. The output circuit is composed of four rectifier diodes and an output capacitor. The voltage of the two ends of the output capacitor is output direct-current voltage. The invention further discloses a control method of the phase-shift full-bridge converter circuit. By means of the circuit and the method, full-bridge soft switching of the phase-shift full-bridge converter circuit is achieved, switching loss is reduced, and efficiency is improved.
Owner:成都芯通软件有限公司

Inductor-capacitor quasi-resonance-based equalization circuit and control method thereof

The invention discloses an inductor-capacitor quasi-resonance-based equalization circuit. The equalization circuit comprises a battery pack and an inductor-capacitor quasi-resonance unit and also comprises a gating switch network and a master controller, wherein the gating switch network is connected with a battery pack and the inductor-capacitor quasi-resonance unit; and during the equalization process, the master controller controls the gating switch network and the inductor-capacitor quasi-resonance unit so that the inductor-capacitor quasi-resonance unit is switched in states of charging, discharge and resonance in a circulation way, and a battery with highest energy transfers the energy to a battery with lowest energy through an inductor-capacitor. By the equalization circuit, zero-current switching of a switch can be achieved, zero-voltage differential equalization among batteries is achieved, and the technical effect of higher speed than that of an existing quasi-resonance circuit is achieved. By the equalization circuit, the switch loss of a switch device can be greatly reduced, and the equalization circuit has the advantages of a few energy storage devices, small circuit size and fast equalization speed, and is applicable to a battery management system of an energy storage device in an electric vehicle or an energy storage power station.
Owner:SOUTH CHINA UNIV OF TECH

Solar photovoltaic charge control device

The invention discloses a solar photovoltaic charge control device. A PWM signal drive component (6) comprises an RC low pass filter (61), a PWM chip (62) and a logic gate circuit (63) which are connected in series, and is used for providing drive signals of an auxiliary switch (31), a main switch (32) and a synchronous rectification switch (33) to a DC-DC conversion component (3) in time sequence according to PWM duty ratio signals of a microprocessor (5). The DC-DC conversion component (3) is composed of the main switch (32) with the two ends being connected with first resonance capacitors (C1) in parallel, the synchronous rectification switch (33) with the two ends being connected with second resonance capacitors (C2) in parallel, the auxiliary switch (31), a resonance inductor (Lr) and a filter inductor (Lf). The DC-DC conversion component (3) is used for sequentially enabling the synchronous rectification switch (33) to be turned off with zero current, the main switch (32) to be turned on with zero voltage and then turned off with quasi zero voltage according to set time of duty ratio, and the synchronous rectification switch (33) to be turned on with zero voltage and drop voltage of the synchronous rectification switch (33) at a steady state by not higher than 0.1 V. The solar photovoltaic charge control device can be widely applied to high-power photovoltaic electricity generation systems.
Owner:HEFEI INSTITUTES OF PHYSICAL SCIENCE - CHINESE ACAD OF SCI

Circuit with active power decoupling single-phase no-voltage switch inverter and modulation method thereof

ActiveCN107546999AReverse recovery inhibitionReduce switching lossesEfficient power electronics conversionAc-dc conversionSingle phaseVoltage source inverter
The invention discloses a circuit with an active power decoupling single-phase no-voltage switch inverter and a modulation method thereof. The circuit comprises a direct-current power supply, three groups of bridge arms, a filter inductor of the inverter and a power grid, a filter inductor and an energy-storage capacitor decoupled by active power, an auxiliary switch comprising an anti-parallel diode connected between the direct-current power supply and a bus of the three groups of bridge arms, a resonance branch circuit consisting of a clamping resistor and a resonance inductor, and a capacitor, wherein the three groups of bridge arms comprise two groups of full-bridge single-phase inverters and an active power decoupling group, and each group of bridge arms is composed of two full control type switches with anti-parallel diodes; and the main switch is connected with two ends of the auxiliary switch in parallel. According to the modulation method, pulse signals of the auxiliary switchand the main switch are synchronized, no-voltage switching-on of all switches can be realized in each switching period, the reverse recovery current of the anti-parallel diode of the main switch is effectively inhibited, the switching loss is little, the circuit efficiency is high, the switching efficiency is improved, and the system power density is improved.
Owner:ZHEJIANG UNIV
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