647 results about "Dc transformers" patented technology

A power factor corrected (pfc) ac-dc converter has a modified boost input and a modified buck output. Unlike the prior art boost input, the boost switch returns to the output, not to ground. Unlike the prior art buck output stage, a third switch connects to the input. This allows much of the input current to pass through the converter to the output. There is no input current measurement, but nearly ideal power factor correction is achieved through “natural modulation.” A preferred pfc ac-dc converter uses a variable dc-dc transformer on its output, as a post regulator, to provide dielectric isolation and to provide voltage level shifting. The output of the pfc ac-dc converter has the control characteristics of a buck converter, so it is a natural mate for the variable dc-dc transformer. An ac-dc buck converter is most efficient at its maximum duty cycle. It cannot regulate for a lower input voltage, but it can reduce its duty-cycle to control for higher input voltages. A variable dc-dc transformer is most efficient at its maximum ratio. It cannot regulate for a higher input voltage, but it can reduce its effective turns ratio to control for a lower input voltage. With a small overlap in their control ranges, both parts of the power system can operate at maximum efficiency. The variable dc-dc transformer controls the output voltage for nominal and low input voltage. The ac-dc buck converter limits over-voltage transients.

The invention discloses a charging adapter, a terminal and a charging control method, and aims to solve the problem that the charging current is difficult to increase in the prior art. The charging adapter comprises an alternating-current transformer, a direct-current transformer, an external charging chip and a micro controller. The output end of the alternating-current transformer is connected with the direct-current transformer and the external charging chip. The micro controller is used for causing the alternating-current transformer to provide direct-current output and causing the direct-current transformer to carry out direct current transformation and output after the charging adapter and the terminal are effectively connected, and used for causing the external charging chip to charge the terminal after handshake connection between the charging adapter and the terminal is established. By adopting the charging adapter provided by the embodiment of the invention, the charging current can be increased, and the charging efficiency can be improved.

A power supply system and power overvoltage safety protection control method, the power supply system comprises an AC/DC switching power supply, a spare battery and at least one DC/DC transformer, and further comprises an overvoltage detection unit which is used for detecting the output voltage of each DC/DC transformer in real time, comparing the output voltage of the DC/DC transformer with a reference voltage and outputting a fault signal. When detecting a dangerous voltage at a later stage output, the system firstly clamps and absorbs a transient dangerous voltage, uses the overvoltage detection unit to detect an overvoltage fault signal synchronously, cuts off the power supply to each transformer from the AC/DC switching power supply and the spare battery, and directly turns off a control chip after converting the fault signal into a proper voltage, thereby realizing the tertiary protection of the system, avoiding the safety risk possibly resulted from the input and output short circuit of the transformer, and improving the reliability of the system.

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 provides a wireless distributed base station power supply system, relating to the wireless communication field. The wireless distributed base station power supply system comprises a battery, an AC-DC transformer, a bus bar, a power distribution unit used for distributing electricity energy, a remote cable and a load. The power distribution unit comprises a boosted circuit and a first switch, the battery and the transformer are in parallel connections via the input end of the bus bar, and the output end of the bus bar is connected with the input end of the boosted circuit; the output end of the boosted circuit is connected with the input end of the first switch, the output end of the first switch is connected with the input end of the remote cable, and the output end of the remote cable is connected with the load. The boosted circuit comprises a boost set point, when the voltage of the bus bar is greater than or equal to the boost set point, the boosted circuit does not work; and when the voltage of the bus bar is less than the boost set point, the boosted circuit starts working. By the above scheme of the invention, and under the situation that the battery supplies power, the cross-section of the cable and the height of the power distribution unit are reduced, the cable material cost is reduced, the distance of the remote cable is improved, and the RRU service life is prolonged.

The invention discloses an extended range type electric vehicle power system based on a fuel battery and a control method for the extended range type electric vehicle power system. The output end of a fuel battery system with a hydrogen pot is connected with an input of a direct current/direct current (DC/DC) transformer through a controllable relay S1; an output of the DC/DC transformer is connected with a lithium iron phosphate power battery pack; the lithium iron phosphate power battery pack is connected with the high voltage input end of a motor controller; the three-phase output end of the motor controller is connected with a driving motor; a whole vehicle controller VMS directly controls an electromagnetic valve for managing hydrogen output and the relay S1 through an input/output (I/O) port, and communicates with the fuel battery system, the DC/DC transformer, a battery management system and the motor controller through controller area network (CAN) buses so as to control a motor to drive the whole vehicle to run and manage the whole power system. The fuel battery system with the hydrogen pot is used as a vehicle-mounted charger for the lithium iron phosphate power battery pack; and a scheme of a vehicle-mounted range extender of an electric vehicle can be provided. The efficiency of the fuel battery system serving as the vehicle-mounted range extender is higher than that of an internal combustion engine; furthermore, the noise is low, and zero emission and zero pollution are realized.

This invention LLC serial resonance DC/DC converter includes a bleeder capacitor, an inverter composed of four serial switches, a resonance circuit, a clamp, an isolation transformer, a commutating circuit and a filter, capable of realizing large input/output voltage regulation sphere with small frequency variable sphere by LLC resonance circuit with dual intrinsic resonance frequency, at the same time, the switch is effectively clamped by a pair of clamp diodes, so that each switch voltage stress is half of the input voltage and ZVS is realized in all sphere without any additional circuit, the commutation diode works at the ZCS state.

The invention relates to a cascade two-way DC-DC converter, composed of two parts: nonisolated two-way DC-DC converter and high-frequency DC transformer, where the former includes circuittopologies such as two-way boost, two-way buck, two-way boost-buck, etc. and the latter is composed of high-frequency inverter/rectifier, high-frequency transformer, and high-frequency rectifier/inverter unit, where the first and fourth ones include push-pull circuit, half-bridge circuit, full-bridge circuit, push-pull forward circuit, double-tube forward circuit, active clamped forward circuit, nonsymmetrical half-bridge circuit, and other circuits. It implements two-way energy flow and electrical isolation, where all its switch tubes are zero-voltage switches, and has the advantage of relatively independent two parts, convenience for control, high conversion efficiency and power density, and simple circuit structure, etc.

This invention teaches power factor corrected 3-phase ac-dc power converters in which the duty-cycles are determined by “natural modulation”, that is, they are forced by a fixed algorithm that has been optimized for efficient switching. The duty-cycles do not regulate the output voltage but they do force the input currents to be proportionately correct for good power factor. A feedback control circuit modulates the effective turns-ratio of a variable dc-dc transformer to regulate the output voltage. For a buck converter, the most efficient duty-cycle is 100%, that is, the buck switch is always on. For a boost converter, the most efficient duty-cycle is 0%, that is, the boost switch is always off. “100% duty-cycle” as defined for a buck 3-phase ac input means that there is no off-time. The switch duty-cycles are as follows: The duty-cycle for the phase with the highest voltage magnitude (the dominant phase) is 100%, and sum of the duty-cycles of the other two phases equals 100%. “0% duty-cycle” as defined for a boost 3-phase ac input means that the input is never short circuited line to line. The duty-cycle for the switch for the phase with the highest voltage magnitude (the dominant phase) is 0%, and switches of the other two phases modulate to control their respective input currents.

The invention relates to a transformer used for realizing balanced current output among multipath outputs, aiming at providing a capacitor isolated type multipath constant current output resonant mode DC/DC transformer. The transformer comprises a DC input, a primary-side topology comprising a plurality of switches, a secondary-side rectifier, and a resonance network comprising two resonance circuit branches, wherein each resonance circuit branch respectively comprises one resonance capacitor and one resonance inductor which are connected in series, and each resonance circuit branch is connected between one output end of the primary-side topology and one input end of the secondary-side rectifier. In the invention, a traditional isolated transformer is omitted, therefore, the circuit structure is simplified, the cost is reduced, and simple and efficient multipath constant source outputs are realized; and the invention is particularly suitable for the driving of multi-series LEDs.

Energy efficient system for lighting is provided that allows variation of length, density of illumination and positioning. The inventive system is particularly suitable for decorative lighting and seasonal display. The lighting system comprises at least one light string having a plurality of light emitting diodes (LEDS) interconnected to a parallel set of power wires maintaining output voltage within a prescribed range. A direct current (DC) transformer is connected to the parallel set of power wires to convert alternating current (AC) input to DC output to control power to the lighting system at relatively low voltage level and less than about fifteen watts. Multiple LED light strings may be connected to the parallel set of power wires to provide decorative lighting displays of desired length, configuration and density of illumination. Accordingly, the unique system provides decorative lighting that is energy efficient and suitable for low cost manufacture compared with conventional incandescent light strings.

The invention discloses a wireless rechargeable electronic bracelet and a wireless charging method thereof. The wireless rechargeable electronic bracelet comprises a bracelet casing and a wireless charge base for charging the same wirelessly. A power supply system comprising a polymer lithium battery, a charge protection circuit, a charge management module and a wireless charge receiving module is mounted in the bracelet casing; the wireless charge receiving module comprises a receiving coil and a rectifying and filtering voltage-stabilizing circuit. The wireless charge base comprises a base box, a transmitting coil and a high-frequency resonance circuit are both mounted in the base box, and the high-frequency resonance circuit is connected with an AC-to-DC transformer which is further connected with an external power supply. The wireless rechargeable electronic bracelet has the advantages of convenience in use. As the electronic bracelet is of the design of the wireless charge technique, the electronic bracelet has better water-tightness, the environmental adaptability of the electronic bracelet is improved, the appearance of the electronic bracelet is fashionable, and the electronic bracelet has ultramodern characteristics.

A distributed power system, wherein a backup boost transformer is connected between a PFC transformer and a FE DC transformer. The backup boost transformer is also parallel connected with a diode. The backup boost transformer only operates in the sustaining time, if the first DC voltage drops gradually, the backup boost transformer will increase this first DC voltage and stabilize it at a preset voltage of the FE DC transformer. Therefore, the capacity of the storage capacitor of the PFC transformer can be fully utilized to have a longer sustaining time and decrease the variation range of the second DC voltage so as to enhance the efficiency and power density thereof.

The invention provides a topological structure of a multi-port DC transformer substation and a control method thereof. The functions of different dual-port DC/DC converters are fused, the topological structure can be interconnected with different types of multiple-voltage-grade offshore DC wind power plants and high voltage DC power transmission systems similar in the way that AC networking is achieved through an AC transformer substation and DC networking is achieved through a DC transformer substation, centralized control of DC power flow can further be conducted, and normal work of the DC power transmission systems at other ends can not be affected when the DC power transmission system at one end breaks down. High reliability and extensibility are achieved, the number of ports can be increased or decreased according to actual demands, and great technological, economical and social significance is achieved.

The invention provides an integrated auxiliary energy supply system for a wind and solar generator, which comprises a solar battery array (1), a wind power generating set (2), a diesel generator (4), a storage battery (5), an auxiliary energy management system (3), an inverter system (6) which changes DC into AC, and a DC transformer system (7), wherein, electric energy output by the solar battery array (1), the wind power generating set (2) and the diesel generator (4) can be supplemented mutually by the auxiliary energy management system (3) for realizing priority use of solar energy and wind energy and stable supply of auxiliary energy, which can utilize the recyclable green energy such as the solar energy and the wind energy maximally, reduce fuel oil consumption and carbon emission, and realize energy supplement by the diesel generator under a windless and lightless severe generation condition so as to guarantee reliability for auxiliary energy supply.

Disclosed is an output power control method for a fuel cell system of a vehicle belonging to fuel cell automobile research and development technology field. A vehicle controller can compute a target torque of a motor according to a driver's intentions (such as key signal, accelerator pedal signal, brake pedal signal, gearshift signal), compute the motor power demand according to the motor rotation speed, and obtain a target output power of the fuel cell system according to the motor power demand and work state signals of the cell; then the vehicle controller can obtain a target input voltage of a DC/DC transformer according to the relationship between the fuel cell output power and output voltage, and send the instruction to the DC/DC transformer. The DC/DC transformer can perform PI closed loop control according to the target input voltage and actual output current, so as to realize direct control on the output power of the fuel cell system. The invention has high control precision, high response speed.

The invention relates to a high-voltage direct-current (DC) transformer and a control method thereof. The high-voltage DC transformer comprises N isolation type low-voltage DC-DC converters. The high-voltage side of each low-voltage DC-DC converter comprises a first mechanical bypass switch (K1), and the low-voltage side thereof comprises a second mechanical bypass switch (K2). During normal operation, a control system allows R isolation type low-voltage DC-DC converters to be in the redundancy state and the rest N-R isolation type low-voltage DC-DC converters to be in the normal state, wherein 0<R<N. When one optional isolation type low-voltage DC-DC converter inside fails, the first mechanical bypass switch (K1) on the high-voltage side of the converter is switched on, and second mechanical bypass switch (K2) on the low-voltage side of the converter is switched off. Regardless of whether the internal circuit fails or not, only N-R isolation type low-voltage DC-DC converters bear high DC voltage, and voltage input and output are not affected when some parts of the circuit is bypassed.

A multi-zone blanket includes a body including first heat zones juxtaposed side-by-side and symmetrically aligned within a body cavity. A first primary heating element passes through each of the first heat zones. A first external controller has an AC/DC transformer electrically coupled thereto. The first controller is electrically coupled and removably attached to the first primary heating element. The transformer is removably coupled to an external power supply source which provides a high voltage input to the transformer. The transformer converts the high voltage input to a low voltage input. The first controller includes a mechanism for providing output control signals to the first heat zones such that each first heat zone can simultaneously and independently generate a selected quantity of heat.

The invention discloses direct-current power spring topology and a control method thereof, wherein definition of a critical load and a non-critical load is similar to current alternating-current ES. DCES is achieved by adopting a DC/DC convertor with bidirectional energy, and meanwhile the position of the non-critical load in current alternating-current ES is changed by adopting a concept of a direct-current transformer to enable the voltage of the non-critical load to be monotonously changed along with changes of the network voltage. When the direct-current voltage output by renewable energy power generation deviates from a normal value, DCES not only can guarantee that the critical load voltage precisely follows a set value, but also can transfer fluctuation of the direct-current voltage to the non-critical load, and therefore automatic balance of the voltage and the power is achieved. The direct current power spring topology and the control method thereof are especially suitable for a roof photovoltaic power generation system and a small wind power generation system and are particularly important to voltage stabilization of a direct-current power system and a direct-current micro grid. After the direct current power spring topology and the control method thereof are adopted, a common user can directly supply power to the critical load through self power generation.

The invention aims at providing a practical plug-in hybrid electric vehicle which can save the charging time and meet the requirements of the steerability and the travelling comfort of drivers. The plug-in hybrid electric vehicle is driven by a driving motor through a speed reducer, and the driving motor is connected with a high voltage power battery by an inverter; the high voltage power battery is respectively connected with a vehicle charger, a quick charging interface and a vehicle electric generator, wherein the vehicle electric generator consists of an internal combustion engine, an electricity generating machine and the inverter; the high voltage power battery is also connected with a 12 V storage battery by a DC-DC transformer. By setting multiple charging ways, the plug-in hybrid electric vehicle can save the charging time, and can meet the requirements of the steerability and the travelling comfort of the drivers since a braking system, a steering system, an air conditioning system and the like are arranged in the vehicle; therefore, the technology is beneficial to further practicability of the plug-in hybrid electric vehicle.

The invention relates to the technical field of power electronics converters, and aims to provide a direct current transformer device used for power distribution. The device comprises a high-frequency transformer, a high-voltage side converter valve and a low-voltage side converter valve, wherein the input side of the high-voltage side converter valve is directly connected with a middle-high-voltage direct current power grid, and the output side of the high-voltage side converter valve is connected with a primary side winding of the high-frequency transformer; the input side of the low-voltage side converter valve is connected with the primary side winding of the high-frequency transformer, and the output side of the low-voltage side converter valve is connected with a low-voltage direct current power grid or an energy storage system. The input sides and the output sides of the direct current transformer device are subjected to high-frequency isolation, a heavy low-frequency transformer is omitted, voltage can achieve a high level due to a modularization design, the cost is lowered, meanwhile, a redundancy design becomes simple and feasible, and the system can be repaired without outage; the switching loss of the device can be lowered by a phase shift control structure to enable the efficiency of the converter to be high; the energy of the direct current transformer system can carry out bidirectional flowing; the whole direct current transformer system has the advantages of simpleness and flexibility in control, efficiency and reliability.

At present, strong extra-high voltage direct-current electric power transmission grids are built in China. Energy is needed to be stored in a storage battery and then transmitted to the grid or the storage battery is needed to be hung on the direct-current electric power transmission grid because of the randomness of power supply from new energy resources. However, a bidirectional direct-current converter has the characteristic of implementing bidirectional flow of the energy through a set of hardware, so that the bidirectional direct-current converter which is suitable for energy transmission between the high voltage electric power transmission grid and the storage battery becomes a hot topic in the research. The invention provides a bidirectional direct-current converter with high buck-boost ratio, which can be applied to high-voltage and high-power applications. Through the invention, the problem of the flow of the energy among modules after the original bidirectional converter is connected in series or parallel. The circuit of the bidirectional direct-current converter is characterized in that a main circuit is a two-stage bidirectional converter, wherein the front stage is an original-edge inversion auxiliary edge rectification type direct-current converter, and the rear stage is a BUCK-BOOST type bidirectional converter. The control mode is that each module is independently controlled so that staggered-frequency control is realized, electromagnetic interference is reduced and the voltage isolation level of drive signals is effectively lowered.

The invention discloses an improved switched capacitor-accessed two-way DC transformer and a control method thereof, and belongs to the technical field of electric power. The transformer is formed by connecting n identical DC conversion units at one port in series and at the other port in parallel; and each DC conversion unit comprises eight semiconductor switches, two auxiliary semiconductor switches, two DC capacitors, a high-frequency inductor and a high-frequency transformer. The method comprises the steps as follows: under the normal condition, high-voltage sides of the n DC conversion units are connected in series and then are connected to a high-voltage DC side through a DC electric reactor; low-voltage sides of the n DC conversion units are connected in parallel and then are directly connected to a low-voltage DC side; when smaller than k DC conversion units have internal faults, the DC conversion units with the faults are directly bypassed; and when an external fault appears at the high-voltage or low-voltage DC side, the semiconductor switches and the auxiliary semiconductor switches of all DC conversion units are turned off and the capacitor voltage can be kept constant. According to the improved switched capacitor-accessed two-way DC transformer, the operation economy and reliability of a device are improved.