55results about How to "Avoid voltage spikes" patented technology

A vehicle generator control system detects a time point at which an electrical load is to be disconnected from the generator output, with the detection being achieved prior to that disconnection time point, and initiates a lowering of the generated current of the generator by an amount equal to the load current of that electrical load. The generated current of the generator is thereby reduced, by the time of the disconnection, to a value whereby substantially no voltage spike is produced in the generator output voltage.

The invention relates to a high-efficiency and low-cost forward-flyback DC-DC (direct current-direct current) converter topology. The forward-flyback DC-DC converter topology comprises a transformer, a main switch tube, a clamp circuit, a first rectification switch tube, a second rectification switch tube, an LC resonance circuit and an output capacitor, wherein a primary winding of the transformer is connected in series with the main switch tube between a first input end and a second input end; the clamp circuit consisting of a clamp capacitor and a clamp switch tube which are connected in series is connected in parallel with the primary winding or the main switch tube; a secondary winding of the transformer comprises a forward winding and a flyback winding; one end making the current flow into the primary winding is a dotted end of the primary winding; the secondary side of the transformer is connected in a manner that: the dotted end of the forward winding is connected to the first output terminal through the first rectification switch tube, and the dotted end of the flyback winding is connected to the second output terminal through the second rectification switch tube; the LC resonance circuit is connected to the first output terminal and the second output terminal and the unlike ends of the forward winding and the flyback winding so as to switch on or switch off the first rectification switch tube and the second rectification switch tube at zero current; and the output capacitor is connected between the first output terminal and the second output terminal.

An alternator (10) has a housing (11), a pair of opposed magnet end plates (12, 13) mounted within the housing (11) a coil plate (14) mounted in and held in position within the housing (11), between the pair of magnet end plates (12, 13). A drive shaft (15) is located within housing (11) and is coupled to the pair of magnet end plates (12, 13). Each magnet end plate (12, 13) has a plurality of permanent magnets (17) disposed thereon. The coil plate (14) has a plurality of magnet wire coils (not shown) embedded therewithin such that they can be seen from both sides of the coil plate (14). In use, turning of the drive shaft (15) causes the magnet end plates (12, 13) to move relative to the coil plate (14) thus exciting each magnet wire coil (not shown) on each side resulting in the generation of an alternating current therein.

The invention discloses an isolated modular multi-level converter, which comprises three phase units linked to high-voltage direct current ports (PH, NH) in parallel; every phase unit is composed of upper and lower bridge arms; outgoing lines of electric joint points (N1, N2, N3) of the upper and lower bridge arms of three phase units are high-voltage alternating current ports (a, b, c) after linking with filter inductors in series; every bridge arm is composed of a single-grade high frequency isolating type submodule with high-voltage direct current side fault current blocking ability and a bridge-arm reactor Lm; the single-grade high frequency isolating type submodule comprises a front grade part, a high-frequency transformer part and a back grade part; the back grade part can block failed current when the high-voltage direct current side has short-circuited failure, thus the failure at the direct current side is removed. The converter structure is simple, and the converter has the advantages that the isolated modular multi-level converter is free from the high-voltage-free side capacitor and voltage-sharing control, and others; the high-voltage direct current side failure voltage can be rapidly cut off.

The invention discloses a drive circuit of a silicon carbide semiconductor field effect transistor. The drive circuit comprises a PWM control circuit, a drive signal amplification circuit, a turn-offcircuit, a gate shunt circuit and a current change rate control circuit, wherein the gate shunt circuit is switched on when the turn-off circuit works to perform shunt of the gate current of a SiC MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) and accelerate the switch-off of the SiC MOSFET; the SiC MOSFET is switched off when the drain-source voltage of the SiC MOSFET is increased toa preset value; the current change rate control circuit is switched off when the drain-source voltage of the SiC MOSFET is increased to the preset value to reduce the leakage current change rate. Thegate shunt circuit is arranged to perform shunt of the gate output current in the SiC MOSFET switch-off process and speed up the decreasing speed of the gate-source voltage so as to improve the switch-off speed of the SiC MOSFET; and besides, in the switch-off process of the SiC MOSFET, the switch-off of the current change rate control circuit reduces the leakage current change rate so as to reduce the voltage peak when the SiC MOSFET is switched off, the two circuits cooperatively act to achieve the voltage reduction speed and the low-voltage peak of the high gate-source voltage and ensure the safety operation of the SiC MOSFET.

The invention discloses a high-frequency isolated multi-low voltage DC bus collecting photovoltaic medium voltage grid-connected power generation system comprising a plurality of arrays of concentrated photovoltaic battery packs, and an array of each concentrated photovoltaic battery pack and an isolated modular cascade converter module group corresponding to three phases are connected in parallel. The system has the advantages of solving the problem of three-phase power imbalance caused by partial shadow; achieving the independent MPPT control and improving the power generation efficiency; reducing the DC side voltage and improving the stability and the safety; improving the system scalability and the redundancy; eliminating or reducing secondary power fluctuation of an independent capacitor at the low-voltage DC bus connecting portion, thereby greatly reducing the size of the individual capacitor at the low-voltage DC bus connecting portion.

The invention discloses a high-frequency link technology-based isolated modular cascaded converter, which is capable of achieving conversion from low voltage DC to high voltage DC. Single-phase and three-phase topological structures of the converter are formed by single-stage high-frequency isolation modules, wherein the three-phase structure can be in star connection or delta connection; each module comprises an upper submodule and a lower submodule; and each submodule comprises four parts, namely a front-stage active H bridge, a high-frequency transformer, a back-stage active H bridge and avoltage clamping circuit. The high-frequency link technology-based isolated modular cascaded converter belongs to single-stage power conversion, so that high voltage sides of various modules do not need to be supported by a capacitor any more; and compared with a two-stage modular cascaded converter, the high-frequency link technology-based isolated modular cascaded converter has the advantages that use of the capacitor can be reduced, the volume and the cost of a device are reduced, and meanwhile, the problems, such as secondary side current commutation and voltage spike of a traditional single-stage converter are solved.

The invention discloses a high-transformation ratio bidirectional DC/DC converter based on a coupling inductor, and belongs to the field of power electronics. The bidirectional DC/DC converter comprises a high-voltage power supply end VH, a low-voltage power supply end VL, a high-voltage filter capacitor CH, a low-voltage filter capacitor CL, a high-transformation ratio boost-buck structure composed of an intermediate capacitor C1, a coupling inductor T, a first switch tube S1 and a body diode D1 thereof, a third switch tube S3 and a body diode D3 thereof, a fourth switch tube S4 and a body diode D4 thereof and an active clamping circuit consisting of a clamping capacitor C2, a second switch tube S2 and a body diode D2 of the second switch tube S2. The high-transformation ratio bidirectional DC/DC converter is simple in circuit structure and can realize the higher voltage transformation ratio, the voltage stress of a switching device is small, and the circuit loss is reduced.

A switch circuit capable of preventing voltage spike, includes an input end for receiving an input voltage, an output end for outputting an output voltage, a switch unit for controlling an electrical connection between the input end and the output end according to a control signal, a protection unit for generating the control signal according to an input current passing through the input end, and a first parasitic transistor for controlling an electrical connection between a second end and a third end according to the control signal, wherein when the input current is greater than a threshold value, the switch unit turns off electrical connection between the input end and the output end according to the control signal, and the first parasitic transistor turns on electrical connection between the second end and the third end of first parasitic transistor according to the control signal to reduce variation of input current.

The invention relates to an output dynamic regulation circuit of a low dropout regulator (LDO). A digital circuit is combined with an analog circuit, a load control circuit generates control signals according to changing of load, and a dynamic output control circuit in the LDO can dynamically control assemblies designed proportionally and with different current output capabilities to output required current. The load control circuit can control changing of the load and LDO output current at the same time to achieve dynamic fast accurate matching of the load and required current. When the load changes, the circuit can adjust the magnitude of the output current so as to meet output requirements and eliminates impact on output voltage when the load changes suddenly. Meanwhile, the output dynamic regulation circuit adopts an interlaced wire distribution technology to place the dynamic output control circuit and an LDO output circuit at intervals, improves responding speed of the output circuit, reduces interference on the LDO circuit caused by power source noises and improves performance of the LDO circuit.

The invention provides a push-pull switching power supply topological structure. The problem that energy of magnetic inductance in a transformer must be maintained on a secondary side when a traditional push-pull switching power supply is in dead time is solved. To maintain the energy of the magnetic inductance, a follow current conduction circuit must be formed on the secondary side of the transformer. For a push-pull circuit, two rectifier diodes are usually used to achieve the purpose, but the premise to ensure the reliable conduction of the diodes is that a load large enough must be available to generate a forward current that can be sufficiently reliably conducted. In addition, in an instant when an inverter switch tube of the push-pull circuit, a very high voltage spike is generateddue to the leakage inductance of the transformer, and a switching tube buffer circuit is usually used to solve the problem. According to the push-pull switching power supply topological structure, a magnetic inductance magnetic inductance circuit is added on a primary side, to maintain the energy of the magnetic inductance on the primary side, so that the voltage spike can be generated in an instant of switching tube turn-off, and the burden on the buffer circuit is reduced.

The invention belongs to the technical field of frequency converters and relates to a driving and protecting circuit for an inversion module. The circuit comprises a driving circuit, an overvoltage clamping circuit, a gate voltage reduction circuit, a soft turn-off circuit and an overcurrent protection circuit; the gate voltage of the inversion module is clamped to be in a specific voltage range through the overvoltage clamping circuit, and therefore, the problem that the inversion module is damaged due to over-high gate voltage in case of over-high current is solved; the gate voltage of the inversion module is reduced through the gate voltage reduction circuit; and the soft turn-off circuit performs soft turn-off on the inversion module before a driving optocoupler is not blocked; under the condition that the gate voltage reduction circuit or the soft turn-off circuit works, overlarge current signals can be fed back to an upper computer controller through an isolation optocoupler, anddriving signals are blocked, and therefore, the inversion module is prevented from repeatedly performing overlarge current protection on the inversion module. Compared with an intelligent optocouplerdriving circuit, the driving and protecting circuit of the invention is lower in cost. Compared with a common optocoupler driving circuit, the driving and protecting circuit is more stable and reliable.

The invention relates to a switching tube protection circuit and a switching device, the protection circuit comprises a sampling circuit, an absorption buffer loop and a processing circuit, the sampling circuit is connected with a first end and a second end of a switching tube, the absorption buffer loop is connected with the first end and the second end of the switching tube, and the processing circuit is connected with a control end of the switching tube, the sampling circuit and a control device. When the voltages of the first end and the second end of the switching tube are too high, the switching tube can be switched off through the processing circuit, and the voltage is absorbed by the absorption buffer loop, so that a voltage peak between the first end and the second end of the switching tube is avoided, the effect of protecting the switching tube is achieved, and the operation reliability of the switching tube is improved.

The invention discloses an electric bridge circuit used for an inverter or a rectifier, and relates to the technical field of power electronics. The electric bridge circuit comprises a first switch, asecond switch, a third switch and a fourth switch which are connected in series and electrically connected between positive and negative direct current voltage sources, wherein the first switch and the second switch are in anti-parallel connection with a first diode; the first switch and the second switch at least comprise a combined field effect transistor; the third switch and the fourth switchare in anti-parallel connection with a second diode; the third switch and the fourth switch at least comprise a combined field effect transistor; the combined field effect transistor comprises a highvoltage withstand field effect transistor and a low voltage withstand field effect transistor with electrically connected sources or drains. Parasitic diodes in the combined field effect transistor are in series-opposing connection, so that the access of a follow current in the parasitic diodes is blocked, so that switch loss and spike voltage caused by the follow current are reduced.

A high-voltage feed-through contains a securing flange for securing the high-voltage feed-through to a wall. The securing flange contains a retaining part and a moving part, wherein the moving part is mounted relative to the retaining part such that it can rotate in relation to a longitudinal direction of the high-voltage feed-through. An electrical device contains a fluid-tight housing and the high-voltage feed-through. A device connection part is provided for receiving and contacting the high-voltage feed-through.

A system and method for controlling switching in an AC-AC converter is disclosed. A controller for the AC-AC converter determines a direction of current flow on supply lines that provide AC power to the AC-AC converter and determines a switching pattern for each of a plurality of line-side switches and each of a plurality of floating-neutral side switches in the AC-AC converter based on the determined direction of current flow on each of the supply lines. The controller causes the line-side switches and the floating-neutral side switches to operate in an ON or OFF condition according to the determined switching pattern, such that a controlled current flow is output from the AC-AC converter. The controller also implements a safe-switching routine when transitioning from a first switching pattern to a second switching pattern that prevents a non-zero current from being interrupted during the transitioning between the first and second switching patterns.