94results about How to "Wide load range" patented technology

Light load efficiency of a power factor correction circuit is improved by adaptive on-time control and providing for selection between a continuous conduction mode and a discontinuous conduction mode wherein the discontinuous conduction mode increases time between switching pulses controlling connection of a cyclically varying voltage to a filter/inductor that delivers a desired DC voltage and thus can greatly reduce the switching frequency at light loads where switching frequency related losses dominate efficiency. The mode for controlling switching is preferably selected for each switching pulse within a half cycle of the cyclically varying input voltage. A multi-phase embodiment allows cancellation of EMI noise at harmonics of the switching frequency and adaptive change of phase angle allows for cancellation of dominant higher order harmonics as switching frequency is reduced.

A biocompatible material may be configured into any number of implantable medical devices including intraluminal stents. Polymeric materials may be utilized to fabricate any of these devices, including stents. The stents may be balloon expandable or self-expanding. The polymeric materials may include additives such as drugs or other bioactive agents as well as radiopaque agents. By preferential mechanical deformation of the polymer, the polymer chains may be oriented to achieve certain desirable performance characteristics.

A two-gain-stage linear error amplifier is provided with frequency compensation and independently selectable stage gains and a reasonably small compensation capacitor to promote stability with a reasonable phase margin over a wide load range so that the invention is useful as a low drop out (LDO) voltage regulator circuit device that is stable over a wide load range.

The invention discloses a wide-range bidirectional conversion circuit and a control method. The wide-range bidirectional conversion circuit comprises a three-stage bidirectional converter and a control unit, and the three-stage bidirectional converter is formed by sequentially connecting a non-isolated DC/DC converter, an isolated DC/DC converter and a DC/AC inverter. When the system works in theforward direction, a direct-current power supply or energy storage equipment realizes grid-connected energy feedback through the non-isolated DC/DC converter, the isolated DC/DC converter and the DC/AC inverter; and during reverse working, an alternating voltage supplies power to a direct-current load or charges an energy storage device through a rectifying circuit, the isolated DC/DC converter and the non-isolated DC/DC converter. In order to adapt to different power levels and realize higher input current ripple control, the non-isolated converter adopts a multi-phase interleaved parallel structure; and in order to further broaden the requirements of input and output ranges in practical application, the isolated converter can be controlled by adopting a full-bridge/half-bridge variable structure. The whole system has the advantages of wide input direct-current voltage range, wide output alternating-current voltage range, wide load range, small current ripple, high-frequency isolation, high efficiency, energy conservation, environmental protection and the like.

A biocompatible material may be configured into any number of implantable medical devices including intraluminal stents. Polymeric materials may be utilized to fabricate any of these devices, including stents. The stents may be balloon expandable or self-expanding. The polymeric materials may include additives such as drugs or other bioactive agents as well as radiopaque agents. By preferential mechanical deformation of the polymer, the polymer chains may be oriented to achieve certain desirable performance characteristics.

The invention provides an AC servo system load torque and rotation inertia identification method and aims to achieve the fine dynamic and static characteristics of highly accurate control of a servo system according to the effect on the system performance by the permanent magnet synchronous AC servo system load rotation inertia and load torque. The method adopting the load inertia and motor rotor inertia as an entire inertia, allowing a servo system to perform regular forward and reverse speed increasing and decreasing movement, adopting a load disturbance torque state observer to observe the load disturbance torque changes of the motor, acquiring a model disturbance torque, adopting the integration identification algorithm, and identifying the system rotation inertia through mathematical derivation.

A supercharged engine has a geometric compression ratio ser to 16 or more and is designed to perform a compression self-ignition combustion under an air-fuel ratio leaner than a stoichiometric air-fuel ratio at least in a low engine speed range. On a lower engine load side than a given engine load within an engine operating region at which the compression self-ignition combustion is performed, a fresh air amount is reduced and an effective compression ratio (ε′) is increased, as compared with a higher engine load side than the given engine load within the engine operating region, and, on the higher engine load side than the given engine load, a supercharging pressure based on a supercharger (25) is increased to increase the fresh air amount, and the effective compression ratio (ε′) is reduced, as compared with the lower engine load side than the given engine load. This makes it possible to perform the compression self-ignition combustion under a lean air-fuel ratio in a wider engine load range to effectively enhance engine thermal efficiency, while eliminating a need for an operation of forcedly raising/lowering a temperature of fresh air.

In a multi-mode, 2-stroke/4-stroke internal combustion engine operation, by switching the engine stroke from 4-stroke operation to 2-stroke operation so that the combustion frequency is doubled, doubling of the engine power is achieved even at the same work output per cycle. In order to meet the demand of extremely high power, the engine operates in 4-stroke boosted SI operation transitioned from 2-stroke HCCI operation at pre-set level of power and crank speed requirements. By combining the multi-stroke (2-stroke HCCI and 4-stroke HCCI) and multi-mode operation (2-stroke HCCI and 4-stroke boosted SI operation), full load range and overall high efficiency with minimal NOx emission are achieved.

The invention discloses a full bridge topology power supply, a control method and communication equipment. An inductance clamping circuit capable of self-adjusting resonance is arranged in a full bridge topology power supply device, inductance value features can be automatically adjusted with the utilization self-adjusted resonance inductance in the inductance clamping circuit and according to the size of passed current, a control circuit controls each switch tube of a full bridge topology, wide zero voltage switch load range, small circulation energy and small duty ratio loss are achieved, and therefore light loading vice side rectifying loss is reduced, light loading converting efficiency is enhanced, performance of flexible switches of a full bridge is improved, wide load range zero voltage opening up of primary side switch tubes of the full bridge is favorable for being achieved, switch loss is reduced, and efficiency of full load range is improved. Besides, the changing rate of primary side current is lowered by the self-adjusted resonance inductance, the vice side rectifier tube voltage spike is clamped through the self-adjusting resonance inductance clamping circuit, and therefore vice side rectifier tube source drain electrode voltage spike is lowered, and application reliability is improved.

The invention relates to a three-direction rigidity-adjustable vibration isolator. The vibration isolator comprises vertical rigidity-adjustable parts and transverse rigidity-adjustable parts, and specifically comprises an outer shell, a functional platform, a central screw, an upper central support, a lower central support, eight arched spring pieces, a central metal rubber net and four horizontal guide rails, wherein the eight arched spring pieces, the central screw, the upper central support and the lower central support form a vertical rigidity adjusting mechanism of the vibration isolator; and the central metal rubber net, the functional platform and the four horizontal guide rails form a transverse rigidity adjusting mechanism of the vibration isolator. According to the three-direction rigidity-adjustable vibration isolator, the interval between the upper central support and the lower central support is adjusted through rotating the central screw, the span among the four pairs of spring pieces is changed, and vertical rigidity is adjusted; the four sliding guide rails are rotated, acting force is applied to the central metal rubber net, friction between internal clearances of the central metal rubber net and a metal winding wire is changed, and transverse rigidity is adjusted; and the three-direction rigidity-adjustable vibration isolator is high in mounting adaptability and performance stability.

A gas turbine system (1) including a burner arrangement having a tubular combustion chamber (5), a turbine (6) and a transition duct (7) connecting the combustion chamber (5) and the turbine (6), wherein the transition duct (7) is provided with an axially extending cooling air channel (11). The transition duct (7) includes a plurality of axially extending cooling air channels, and wherein each cooling air channel (11) is provided with one single inlet (12) opened to the outside of the transition duct (7) and with one single outlet (12) opened to the inside of the transition duct (7).

The invention discloses a two-way digital DC-DC convertor with a wide load range. The two-way digital DC-DC convertor comprises a high-voltage end, a low-voltage end, a dsPIC30F single chip microcomputer and a transformer. The output end of the dsPIC30F single chip microcomputer is connected with a drive circuit which is provided with a plurality of PWM output ends; the high-voltage end is connected with a high-voltage part rectifying circuit, the low-voltage end is connected with a low-voltage part rectifying circuit, and the transformer is arranged between the high-voltage part rectifying circuit and the low-voltage part rectifying circuit; the output end of the drive circuit is respectively connected to the control end of the high-voltage part rectifying circuit and the control end of the low-voltage part rectifying circuit. Dead time of phase-shifted full-bridge control is adjusted according to the magnitude of loads, meanwhile different rectification modes are selected according to the magnitude of the loads, and therefore the convertor has high efficiency within the wide load range. The convertor is provided with an active clamping circuit preventing vice edge parasitic oscillation, so voltage overshoot can be effectively prevented. Accordingly, the two-way convertor is especially suitable for occasions having a high requirement for efficiency of convertors and a requirement for large changes of the loads.

The invention discloses a high-efficiency photovoltaic grid connected inverter, and belongs to the technical field of power electronic converters. The high-efficiency photovoltaic grid connected inverter comprises a DSP controller, a first MOS pipe, a second MOS pipe, a transformer, a driving circuit, sampling circuits, an inductor, capacitors and a load, wherein the transformer comprises a primary winding and two secondary windings. In the field of photovoltaic power generation, a DC-DC conversion part is a key part of the inverter; at present, a DC-DC conversion part adopts a hard switching technology generally, so that the electric energy conversion efficiency is too low, and meanwhile, since voltage stress and current stress in a circuit are too high, relatively strong electromagnetic interference is caused. Therefore, an LLC resonant conversion technology is adopted, self parasitic parameters of components are fully used, the voltage stress and the current stress are reduced, a switching frequency can be equal to a resonant frequency, and the conversion efficiency is improved. The high-efficiency photovoltaic grid connected inverter is especially suitable for being used on occasions where requirements on the efficiency of the inverter are relatively high.

An elevator system includes at least one elevator car and at least one counterweight, which can be moved in opposite directions from each other on at least one guide track in an elevator shaft by a support apparatus guided over a traction sheave of a drive. At least one monitoring device detects a slackening of the support apparatus, wherein the monitoring device is disposed at a deflection roller for the support apparatus.

The active vibration-isolating device of the invention is used for preventing vibrations due to ground motions or running of an automobile from being propagated to a platform which is disposed in, for example, a semiconductor device factory or a laser device factory, and on which various kinds of equipment are to be mounted, and also from causing the platform to vibrate. The device has: an air spring which elastically supports a platform; a piston-like member which abuts against and supports the platform; plural piezoelectric actuators which can be externally controlled; a working fluid such as an aqueous solution of ethylene glycol which transmits driving displacements of the piezoelectric actuators to the piston-like member via piston members which are respectively fixed to ends of the piezoelectric actuators in a driving direction x; and a fluid path in which the working fluid is hermetically filled. The load of equipment mounted on the platform is shared by the air spring and the piston-like member, thereby enabling the spring rate to be reduced. Therefore, the resonance frequency can be set lower. As a result, vibration-isolating performance and vibration-damping performance can be surely adequately exerted on vibrations in a wide frequency range including a low-frequency region, and a wide load range.

A regulator circuit supplies an output voltage V_OUT to a load. A second transistor is arranged in parallel with a first transistor, and has a relatively small size. A feedback circuit generates a first feedback signal and a second feedback signal according to the output voltage V_OUT. A first error amplifier controls the first transistor such that the first feedback signal approaches a first reference value. A second error amplifier controls the second transistor such that the second feedback signal approaches a second reference value. In a light-load state, the operation of the first error amplifier is maintained.

A biocompatible material may be configured into any number of implantable medical devices including intraluminal stents. Polymeric materials may be utilized to fabricate any of these devices, including stents. The stents may be balloon expandable or self-expanding. The polymeric materials may include additives such as drugs or other bioactive agents as well as radiopaque agents. By preferential mechanical deformation of the polymer, the polymer chains may be oriented to achieve certain desirable performance characteristics.

A rotating modulation radial spherical permanent-magnet biased magnetic bearing mainly comprises a stator system, a rotor system and a rotating modulation system, wherein the stator system mainly comprises upper spherical stator cores, lower spherical stator cores, field coils, magnetism isolating rings, upper magnetic-conductive rings, lower magnetic-conductive rings, permanent magnets, a stator sleeve and stator locking nuts; the rotor system mainly comprises spherical rotor cores, a rotor sleeve and rotor locking nuts; and the rotating modulation system mainly comprises a magnetic bearing stator mounting plate, a rotating modulation rotor bearing sleeve, rotating modulation bearings, rotating modulation rotor locking nuts, an ultrasonic motor rotor, an ultrasonic motor stator, a rotating modulation stator bearing sleeve and rotating modulation stator locking nuts. The rotating modulation radial spherical permanent-magnet biased magnetic bearing has the rotating modulation function, the stator is driven to rotate by the ultrasonic motor, and angular rate errors of the rotor, caused by gyro drift, are eliminated, so that the control precision of the magnetic bearing is improved.

A driver circuit includes a load control circuit for supplementing a light emitting diode (LED) load in a low load condition. The low load condition corresponds to an output voltage across the LED load below a predetermined threshold voltage. The driver circuit includes an isolation transformer. A primary side circuit is coupled to a primary winding of the isolation transformer and includes a constant current control integrated circuit (IC) and a switch. The constant current control IC controls an output current to the LED load. A load control circuit is coupled to across the LED load and includes an auxiliary load which ensures that the isolation transformer operates in a continuous mode. The auxiliary load supplements the LED load with in a low load condition, but not in a high load condition. The auxiliary load may be configured to quickly discharge an output capacitor in a power off condition.

A radio frequency generator, includes an input voltage unit, a smart power unit, a voltage acquisition unit, a power amplifier unit, an output unit, a load unit, a current acquisition unit, a processor unit, a signal transmission and drive unit and an input control unit. The present application combined advantages of the high-frequency electric knife and the radio frequency ablation device, can be used for both cutting and coagulating the target tissue, and the ablation or treatment to the target tissue. This radio frequency generator has high versatility, can be used as standard component to produce and manufacture. Different medical radio frequency manufacturers can produce and manufacture their own products to meet clinical needs of different clients and different departments for example, by changing a small quantity of peripheral circuits or software.

A method and system for controlling a pulverized coal fired boiler wherein the flow of a coal/air mixture flowing to each burner is monitored and transmitted to a distributed control system. The distributed control system also monitors and controls the position of dampers in a splitter that feeds the coal/air mixture to the burners. The dampers are controlled in a closed loop fashion to achieve a optimal boiler performance.

A test rig for testing a component in a wind turbine is proposed. The test rig has an adjustable radial weight arrangement mounted on a rotatable shaft; a driving means for rotating the shaft at a shaft rotational velocity; and an adjusting means for adjusting the centre of mass of the adjustable radial weight arrangement relative to the shaft while the shaft is rotating. A wind turbine test setup for testing components of a wind turbine has a test rig mounted to a component such that centrifugal forces generated by the rotating radial weights during operation of the test rig are transferred as lateral forces to the wind turbine component under test.