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687 results about "Power diode" patented technology

A power diode is a crystalline semiconductor device used mainly to convert alternating current (AC) to direct current (DC), a process known as rectification. Found in the power supply circuits of virtually all modern-day electrical and electronic equipment, a power diode's function is akin to a mechanical one-way valve.

Vehicle-mounted fuel cell and storage cell directly paralleled power system with super capacitor

The invention relates to a vehicle-mounted fuel cell and storage cell directly paralleled power system with a super capacitor. The power system comprises a fuel cell galvanic pile, a fuel cell accessory system, a fuel cell controller, a storage battery group, a super capacitor group, a high voltage bidirectional DC/DC (direct current) converter, a small power unidirectional DC/DC converter, a motor controller, a driving motor and a system energy management controller, wherein a high voltage output end of the fuel cell galvanic pile is connected with an anode of a power diode through a high voltage switch K1, and the high voltage output end of the storage battery group is directly connected with a cathode of the power diode and the high voltage output end of the motor controller in parallel through a high voltage switch K2 to form a direct current bus. The super capacitor group is connected with the direct current bus through the high voltage bidirectional DC/DC converter, and the high voltage output end of the storage battery group is connected with the fuel cell accessory system through the small power unidirectional DC/DC converter. According to the system disclosed by the invention, a power supply mode in which galvanic pile output needs large power DC/DC voltage stabilization of a conventional fuel cell is abandoned, and the efficiency is improved; the instantaneous needed power of the direct current bus can be compensated by the arranged super capacitor group, the bus voltage is steadied, and braking energy can be quickly and effectively recycled.
Owner:武汉海亿新能源科技有限公司

Ultra high-power continuous wave planar waveguide amplifiers and lasers

InactiveUS6904219B1Avoid bend lossesLaser detailsOptical fibre with multilayer core/claddingWaveguide amplifierHigh power diode laser
Double clad large mode area planar lasers or amplifiers comprising rare-earth or transition metal doped planar core regions are used to generate near-diffraction-limited optical beams of ultra-high power. The amplified light is guided in the core using different guiding mechanisms in two orthogonal axes inside the core. Waveguiding along a first long core axis is obtained substantially by gain-guiding or thermal lensing. Waveguiding along a second short core axis is obtained by index guiding. This is accomplished by surrounding the planar core region with regions of different refractive index. The long sides of the planar core region are surrounded with a depressed refractive index cladding region. The short sides of the planar core region are surrounded with a cladding region substantially index-matched to the core region. The whole structure is surrounded by an outer cladding region with a low refractive index to enable cladding pumping of the planar waveguide with high-power diode lasers. The rare-earth or transition metal doping level inside the planar core can be constant and can also vary substantially without negatively affecting the waveguiding properties. To avoid bend losses along the long axis of the planar waveguide, the planar core region and the planar waveguide are aligned parallel to each other and the planar waveguide is coiled with the long side of the planar waveguide mounted to a drum. The drum can also be used as a heat sink. A planar waveguide comprising a planar core region can be manufactured using conventional fiber fabrication methods.
Owner:BOSTON LASER

High power diode laser having multiple emitters and method for its production

The invention discloses a high power laser diode comprising a plurality of laser light emitters (2) and a plurality of light collimating means (33), wherein each of the laser light emitters (2) defines, in a direction perpendicular to a direction of propagation (32) of an output laser beam, a fast axis (y) and a slow axis (x), and wherein each of the light collimating means is associated with a laser light emitter and configured for collimating the output laser beam at least in a fast axis (y) direction. In order to enable a simple and cost-efficient assembly of the diode laser with collimating means, having a layered structure consisting of a plurality of plane-parallel substrates. For this purpose, the diode laser comprises planar substrate means (10, 30) which serves to precisely define a distance between a respective laser light emitter (2) and an associated light collimating means to the order of one or several millimetres and to support the collimating means (33) such that the optical axis of said laser light emitters are parallel to each other and for defining a precise location of emitters on the planar substrate (10), preferably at predetermined distance in fast axis direction between said laser light emitters. The collimating means is an array or multiple single of micro-optical lenses having a rear side which is bonded to the upper surface of the planar spacer means. The submounts of the light emitters (2) are mounted to the planar substrate means (10, 30) and to a heatsink (6).
Owner:FRAUNHOFER USA

Split induction three-level photovoltaic grid-connected inverter and control method thereof

The invention discloses a split induction three-level photovoltaic grid-connected inverter and a control method thereof and belongs to the technical field of a power electric transformer. The inverter comprises a power supply circuit (A), a first converting branch (B) and a second converting branch (C), wherein the power supply circuit (A) consists of a direct current power supply and two voltage-dividing capacitors; the first converting branch (B) and the second converting branch (C) respectively consist of a power diode, a split inductance and two power switching tubes. The inverter can be expanded into a three-phase circuit structure according to the capacitance requirement and has the same principle with the single-phase structure. The control method of the inverter comprises two parts which respectively are the hysteresis ring width frequency-fixing control of the inverter side inductance current and the early closing of the high-frequency switch driving signal. The invention does not generate high-frequency leakage current when working in the single-polar PWM modulation mode, and does not have the bridge arm direct-connection danger, and the voltage stress of the power switching tubes and the diode are respectively equal to or smaller than one half of the input voltage.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

On-line detection system and method for work junction temperature of power diode module

The invention discloses an on-line detection system and method for the work junction temperature of a power diode module. According to the on-line detection system and method, on-off of an active switch device is controlled to enable the power diode module to be switched in the turn-on state and the turn-off state. When the power diode module is switched to be turned off from being turned on, currents flowing through the power diode module are converted to a complementary switch tube, the reverse recovery currents of the power diode module can generate corresponding induced voltages on a stray inductor of a conversion circuit, and the induced voltages are related to the reverse recovery currents of the power diode module and also comprise the temperature information of the power diode module. According to the on-line detection system and method for the work junction temperature of the power diode module, the variation condition of the reverse recovery currents comprising the temperature information can be measured on the complementary switch tube only by one low-voltage amplitude detection circuit, and additional high-voltage passive auxiliary elements are of no need. While a driving circuit sends control signals, variation voltages caused by the reverse recovery currents are captured, and high precision and real-time performance are achieved.
Owner:ZHEJIANG UNIV

Neutral point potential balancing control system and method of three-level inverter

InactiveCN103607131AReduce or dampen fluctuationsImprove stabilityAc-dc conversionDc-dc conversionThree levelCapacitance
The invention relates to a neutral point potential balancing control system and method of a three-level inverter. The neutral point potential balancing control system and method are used for conducting effective balancing control over the neutral point potential of the high-power diode clamped three-level inverter and collecting the DC bus voltage of the three-level inverter and the neutral point voltage value of two capacitors on the DC side in real time, sending collected signals to two independent PI regulators to generate corresponding controlled quantities, determining the operating mode of the system and the corresponding on-off state of switching tubes according to the obtained controlled quantities, determining the neutral point potential by the way of meeting the requirement of the turn-off time ratio of switching devices at the same time, determining the constraint condition of a busbar voltage according to the sum of connecting time, and accordingly adjusting the duty ratio of two switching tubes in an improved three-level DC/DC module, and therefore the busbar voltage on the DC side is controlled so that the dynamic voltage-sharing process of two supporting capacitors on the DC side can be achieved. Fluctuation of the neutral point potential of the three-level inverter is effectively reduced or restrained ultimately, system performance is improved, and the responsiveness of the system and the stability of a three-level topology circuit are improved.
Owner:UNIV OF SHANGHAI FOR SCI & TECH

Diode clamping five-level dual buck half-bridge inverter

The invention discloses a diode clamping five-level dual buck half-bridge inverter which comprises a first five-level buck circuit, a second five-level buck circuit, a direct current power input circuit and a load circuit. The inverter is controlled by adopting voltage-current dual closed loop SPWM (Sinusoidal Pulse Width Modulation), the two five-level buck circuits are controlled to work withina half cycle according to the direction of inductive current and the magnitude of output voltage, and five-level PWM (Pulse-Width Modulation) wave output is obtained respectively on two output bridgearms through different switch combination. The invention has the advantages that the advantages of straight through without bridge arms of the dual buck circuits and diode reverse recovery without switching tube are reserved; five-level output is realized, and the harmonic wave content of output voltage is reduced, thus the size of a filter can be reduced, the switching frequency of a PWM part can be reduced, the switching loss can be reduced, and the efficiency can be improved; compared with a half-bridge type inverter, the voltage stress of power devices is reduced so that a switching device of medium or low power is suitable for occasions of high voltage and high power; and only eight power diodes are needed in the circuits, compared with a five-level diode clamping inverter, the quantity of the diodes is reduced by 1/3, and a clamping circuit is simplified.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Alternative-current/direct-current (AC/DC) dual-purpose motor control system

The invention discloses an alternative-current/direct-current (AC/DC) dual-purpose motor control system, which is characterized in that: an electric power electronic part Insulated Gate Bipolar Transistor (IGBT) is adopted as a non-contact controllable switch to form a control main circuit, a digital microprocessor is adopted as a control core to form a micro-controller-based AC/DC dual-purpose motor control system. The control main circuit firstly adopts four power diodes to form a single-phase full-wave rectifier bridge, so an external AC power supply system and an external DC power supply system are unified to an internal DC power supply. An AC/DC dual-purpose motor control topology main circuit is arranged behind the rectifier bridge. The IGBT in the control topology main circuit is connected and disconnected according to a given discipline, so the connection order of different homonymous ends of a motor exciting winding and an armature winding can be realized, and the motor can run in the positive direction and the opposite direction or can be braked in the positive direction and the opposite direction. Due to the adoption of the AC/DC dual-purpose motor control system, the service life of the system is greatly improved, the electric arc and spark of the switch can be eliminated, the size can be reduced, and complicated functions of an AC/DC dual-purpose such as soft starting, stepless speed regulation and the like can be realized. The invention also provides a full-digital communication field bus interface so as to realize the remote monitoring of a field bus.
Owner:SHANGHAI MARITIME UNIVERSITY

Double-Cuk buck-boost output parallel-type converter

The invention discloses a double-Cuk buck-boost output parallel-type converter which is formed by connecting two Cuk-type DC / DC (direct current / direct current) converters capable of achieving the buck-boost output at the output in parallel, and can achieve the DC / AC (direct current / alternating current) single-phase conversion and further achieve the three-phase conversion through expansion. The converter has the following basic functions: the double-Cuk buck-boost output parallel-type converter can achieve the buck-boost conversion and normally serve the function of conversion even if the inputted DC voltage is lower or the variation range of the DC voltage is wider; the problem that the bridge arms are directly connected is avoided in the entire circuit, thus ensuring the high reliability; the follow current is not allowed to pass through the body diode of a switching tube, but flows through an independent diode, so that a power switching tube and a power diode can be respectively subject to optimized design; the design of circuit parameters, which is based on the method for designing a DC Cuk converter, is simple; and the inductive current runs in a continuous state, thus reducing the EMI (electro-magnetic interference). The invention is mainly applicable to the fields of photovoltaic generation, fuel-cell power generation and other power generation based on renewable energy and new energy, in which the level of operating voltage is lower or the variation range thereof is wider.
Owner:YANSHAN UNIV
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