54results about How to "Avoid switching losses" patented technology

A lens driver or lens driver circuitry for an ophthalmic apparatus comprising an electronic system which actuates a variable-focus optic is disclosed herein. The lens driver is part of an electronic system incorporated into the ophthalmic apparatus. The electronic system includes one or more batteries or other power sources, power management circuitry, one or more sensors, clock generation circuitry, control algorithms and circuitry, and lens driver circuitry. The lens driver circuitry includes one or more power sources, one or more high voltage generators and one or more switching circuits.

To provide a fuel cell system that can both improve power generation efficiency of a fuel cell and maintain durability of the fuel cell. A fuel cell system performs control such that when a power requirement for the fuel cell is lower than a predetermined value, a supply of a reaction gas to a fuel cell is stopped to keep an output voltage from the fuel cell equal to a high-potential avoidance voltage that is lower than an open end voltage. The fuel cell system further controls the output voltage from the fuel cell with the high-potential avoidance voltage set to be an upper limit when the power requirement for the fuel cell is equal to or higher than a predetermined value. By setting the upper limit of the output voltage of the fuel cell to be the high-potential avoidance voltage, which is lower than the open end voltage, the catalyst can be inhibited from being degraded by an increase in the output voltage from the fuel cell up to the open end voltage.

In controlling switching elements of a current source inverter, a switching loss in the switching element is prevented according to a normal switching operation for a commutation operation, without requiring any particular control.

In the commutation operation of the current source inverter, a timing for driving the switching elements is controlled in such a manner that an overlap period is generated, during when both a switching element at the commutation source and a switching element at the commutation target are set to be the ON state, a resonant circuit is controlled based on the control of the switching elements having this overlap period, and resonant current of the resonant circuit reduces the switching loss upon commutation operation of the switching elements. By controlling the generation of the resonant current of the resonant circuit by using the control of the switching elements having the overlap period, the resonant current generated by this control renders current and voltage of the switching element at the commutation source to zero when commutation is performed, thereby reducing the switching loss in the commutation operation.

This control method for a fuel cell vehicle includes: a target motor output power obtaining step which obtains a target motor output power corresponding to an accelerator opening degree; and a high output power control step which controls operations of a first DC-DC converter and a second DC-DC converter, such that an output voltage of a power source becomes equal to or larger than a predetermined voltage that is required for securing a desired motor output power, when the target motor output power is larger than a predetermined output power threshold value.

A semiconductor device 1 in which an IGBT region 2 and a diode region 3 adjoining each other are formed on a same substrate 4 is presented. The semiconductor device 1 is provided with a plurality of first gate trenches 11 extending abreast in a first direction in the IGBT region 2 and a plurality of second gate trenches 12 extending abreast in a second direction intersecting the first direction. The first gate trenches 11 and the second gate trenches 12 are not in contact with each other.

In a switching power supply apparatus, a first switching element is controlled by a driving voltage output from a switching control IC. A second switching control circuit controls the on-time of a second switching element so that the time ratio of the on-time of the second switching element to the on-time of the first switching element becomes almost constant with respect to a change in a load current. In a normal load state, since a square wave output from a frequency setting unit within the switching control IC is output with no change, a converter operates in a current-continuous mode. In a light load state, a driving signal generation unit within the switching control IC is subjected to blanking with the period of a signal output from a maximum frequency setting unit and an oscillation frequency is reduced. Accordingly, the converter operates in a current-discontinuous mode.

The present invention relates to a circuit arrangement which comprises at least one 3-level pulse width modulation inverter with a snubber circuit. The snubber circuit is formed by at least one coil (L), two capacitors (Cu, Co) and a series connection comprising four diodes (Dh1-Dh4) poled in the same direction, whereof the two outer diodes (Dh1, Dh4) are in each case directly connected to the input terminals (1, 3) for the positive and the negative pole of the input voltage. The electrical connection between the two inner diodes (Dh2, Dh3) is connected on the one hand via the coil (L) to the input terminal (2) for the centre tap of the input voltage and on the other hand to the middle bridge branch of the pulse width modulation inverter. In one embodiment, the two capacitors (Cu, Co) are in each case connected with one terminal to the electrical connection between one of the inner diodes (Dh2, Dh3) and one of the outer diodes (Dh1, Dh4) and with the other terminal directly to the output terminal (4).

With the proposed circuit, switching losses are completely avoided as a matter of principle with a simple and low-cost design.

A converter for a wind energy installation and a method. The converter includes an inverter which drives a generator via a plurality of phases and an intermediate circuit having an intermediate-circuit voltage between an upper and a lower intermediate-circuit potential. The generator is driven with phase potentials at a variable frequency. A shift value is calculated between an extreme phase potential and one of the intermediate-circuit potentials, a separation value is determined between a middle phase potential and the closest intermediate-circuit potential, and an additional voltage is generated using the separation value as amplitude. The phase potentials are shifted through the shift value and the additional voltage is added to the middle phase potential. Accordingly, the switching elements in the converter do not need to be clocked in every second half-cycle resulting in reduced switching losses and increased current load capacity of the converter.

A model prediction-direct torque control method for a permanent magnet synchronous motor belongs to the technical field of control. The object of the invention is to complete the accurate estimation of torque and flux linkage in a system by using a reduced-order observer, and then to design the model prediction-direct torque control method for a permanent magnet synchronous motor of a hub motor drive system controller through a model prediction control algorithm. The steps include: selecting motor torque and flux linkage as state variables, selecting an objective function enabling the minimumerror between a predicted value and an expected value of torque and flux linkage, and obtaining three-phase voltage for controlling the motor to finish control over the PMSM. The model prediction control algorithm applied by the invention can effectively deal with the multi-input multi-output and multi-constraint optimization control problems, replaces a hysteresis loop comparator and a switch selection module of conventional direct torque control, avoids the upper and lower limit pulsation of the hysteresis loop and unnecessary switching losses, and effectively suppresses the torque pulsationof the drive motor.

The invention discloses a base region gradient P<+>-N-N<+> type SiC ultrafast recovery diode manufactured on a 4H type single crystal silicon carbide epitaxial layer and a process. An anode/(P<+>)4H-nc-SiC/(N) slowly changes into a 6H-nc-SiC/(N)4H-c-SiC/(N<+>)4H-c-SiC/cathode. The base region gradient P<+>-N-N<+> type SiC ultrafast recovery diode comprises an N<+> type 4H-c-SiC substrate, an N type 4H-c-SiC epitaxial layer, an N type 6H-nc-SiC gradually-doped and grain-gradient multilayer film and a P<+> type 4H-c-SiC single layer film, wherein the outer sides of the N<+> type 4H-c-SiC substrate and the P<+> type 4H-c-SiC single layer film are in ohm connection with an anode NiAu and an anode TiAu respectively. The device structure is made by using a PECVD (Plasma Enhanced Chemical Vapor Deposition) technology. The process has the advantages of shortening the reverse recovery time, inhibiting surge current and lowering the process temperature.

A switching device is disclosed in which electric current through a rectification circuit, depending on whether a main switching element turns on or off, and thus electric current from the rectification circuit flows through whichever of first and second sub-switching elements, turns on. By controlling the turning on and off of the first and second sub-switching elements, the switching is performed which determines through which of the first and second output circuits the electric current from the rectification circuit flows. Thus, a voltage that is a result of transforming a voltage from a DC power supply in response to the electric current flowing through the first output circuit, is output from a first output terminal, and a voltage that is a result of transforming a voltage from the DC power supply in response to the electric current flowing through the second output circuit, is output from a second output terminal.

The invention relates to a control device used in a resonance type DC/DC converter. The control device is used for controlling one switch unit of the resonance type DC/DC converter so as to change over power supply and output an output message. The control device comprises a frequency modulation controller which produces a synchronous signal according to the output message, and a pulse sizer which receives the output message and the synchronous signal and produces a drive signal to turn on or off the switch unit according to the output message and the synchronous message. In addition, the drive signal comprises a working section where frequency of the drive signal is essentially the same with that of the synchronous signal, and a non-working section where the drive signal consistently keeps a low potential.

A control voltage is generated at a control input of a semiconductor circuit breaker by an actuation circuit at switching flanks of a switching signal, said control voltage having a profile which is flattened in relation to the profile of the switching signal. With the disclosed method, the switching losses in a semiconductor circuit breaker are reduced. By defining a value for a switching parameter of a control device of the actuation circuit, the switching behavior of the actuation circuit can be influenced by the switching parameter. A specific parameter value of the switching parameter can be varied during operation of the actuation circuit.

The present invention relates to a power supply device for supplying power to a load, preferably a LED, comprising a first circuitry (12) with an inverter unit (24) adapted to provide an AC voltage, preferably a rectangular voltage, and a resonant circuit (30) with a capacitance (32) and an inductance (34), a second circuitry (14) with a rectifier unit (42), a switch (64) and said load (60), said switch being adapted to switch said load on and off, a controller unit (16) adapted to control said switch (64) as to adjust the power provided to said load (60) without any measurement signal from said primary circuitry (12), and a transformer (18) with a primary side (20) and a secondary side (22), said primary side being connected to said first circuitry (12) and said secondary side (22) being connected to said second circuitry (14), preferably said rectifier, so that said first and second circuitries are galvanically isolated.

The invention discloses an AC/AC injection type inductance coupling type wireless energy transmission apparatus. The apparatus comprises a bidirectional flyback energy storage unit, an energy transfer unit, a high frequency resonance emission unit and a receiving end resonance unit, wherein the energy transfer unit enables the bidirectional flyback energy storage unit and the high frequency resonance emission unit not to intervene each other; the pulse type energy injection at the emission end of the apparatus is controlled to enable the apparatus to transmit energy to the receiving end at a switching frequency that is far below the resonance frequency; the switch loss caused by an overhigh operating frequency of the switch tube is avoided; the wireless energy transmission efficiency of the apparatus is improved; due to the operating characteristics of the bidirectional flyback converter, the apparatus can directly perform energy collection on the alternating current input voltage to realize an AC-to-AC emission end energy transfer process; the volume and the cost of the apparatus are optimized, and the reliability of the apparatus is improved, so that the apparatus has actual practical value; and meanwhile, a first-level AC/AC converter is adopted, so that unity power factor correction can be realized, the cost can be lowered, and the system efficiency is improved.

The invention discloses a light-dimming driving circuit of an LED lamp, a light-dimming driving chip of the LED lamp, and a control circuit loaded by the LED. The light-dimming driving circuit comprises a filter module, a maximum voltage selection module, a first comparison module, a follower module, a second comparison module, a trigger module and a switch module; the filter module filters the analog voltage signal to obtain the DC voltage; the maximum voltage selection module obtains the maximum between the first reference voltage and the DC voltage; the first comparison module outputs a first reset signal or a second reset signal according to sampling voltage and the voltage output by the maximum voltage selection module; the follower module outputs the first low-resistance voltage andthe second low-resistance voltage according to DC voltage; the second comparison module outputs a first pulse signal or a second pulse signal according to the voltage output by the follower circuit and a second reference voltage. The light-emitting state of the LED lamp can be changed in real time through the first reset signal, the second reset signal, the first pulse signal and the second pulsesignal.

The invention relates to a motor control method and device, computer equipment and a storage medium. The method comprises the steps: obtaining a current rotating speed value of a motor; determining atarget carrier frequency value of the motor according to the current rotating speed value and a preset carrier frequency calculation model, wherein the carrier frequency calculation model is determined according to multiple sets of given rotating speed values and carrier frequency calibration values of the motor, the carrier frequency calibration values being determined according to system efficiency values of the corresponding given rotating speed values at different carrier frequency values, the system efficiency values being the total efficiency values of the motor and a controller of the motor; and adjusting the carrier signal input into the motor according to the target carrier frequency value. By adopting the method, the system efficiency can be improved globally.