121 results about "Stray loss" patented technology

The invention relates to an optimization design method for a high-efficiency synchronous motor of a new energy automobile. The method includes the steps that an iron loss computation model is established for the permanent magnet synchronous motor, and magnetic density changes are researched, so that magnetic hysteresis losses and no-load iron losses corresponding to different sub-harmonic magnetic fields are obtained; theoretical analysis and finite element solving are performed on load stray losses of the permanent magnet synchronous motor of the automobile in the aspects of a stator, a rotor and a permanent magnet, and permanent magnet eddy-current losses are restrained; a water cooling system of the motor is analyzed, influences on the high-efficiency range and weak magnetic performance by parameter matching are analyzed, the rotor structure form, polar trough matching and no-load counter electromotive force of the motor sample are designed, and the motor sample is tested. Through analyzing the magnetic field features, the magnetic hysteresis losses and eddy-current losses, the degree and distribution of rotor losses and the permanent magnetic eddy-current losses are accurately computed under matching between different rotor structures and polar troughs, and therefore effective measures for restraining the rotor losses and permanent magnetic eddy-current losses are found.

The invention discloses a low-uncertainty stray loss test system of a motor, which is characterized by comprising a rectifying unit, a test power supply, a simulating constant torque load and a torque / rotating speed sensor, wherein the rectifying unit respectively connects direct current obtained by bridge-rectifying alternating current commercial power to the test power supply and the simulating constant torque load; the test power supply is sequentially connected with an electrical parameter measuring control, output control and test motor after modulating the direct current into frequency converting static alternating current power supply; the simulating constant torque load is connected with a load motor after modulating the direct current into a controllable power supply of a constant torque load; and the torque / rotating speed sensor is respectively connected with a data measurement and test motor and the load motor. Compared with the prior art, the invention has the advantages of simple test system, convenient operation, high test precision and good stability, can meet an efficiency test of an efficient and superefficient motor of 0.37-375kW, has an uncertainty value lower than 0.4 percent and lays a certain foundation for China to be dedicated to research and development of the high-efficiency motor.

The invention relates to a single-layer short isometric winding of a 48-slot 4-pole three-phase asynchronous motor, belongs to the field of the structural design of motors, and aims at providing the single-layer short isometric winding which is capable of improving motor efficiency and saving wires, and is convenient to wind and simple in embedding the wires. All the pitches, shapes and sizes of coils in the single-layer short isometric winding of the 48-slot 4-pole three-phase asynchronous motor are the same. The pitches of the coils are 9, and the wires are embedded on the single-layer short isometric winding in an overlapping method, and the single-layer short isometric winding is connected in a salient pole connection method and is suitable for manufacturing and maintenance of the three-phase asynchronous motor provided with a stator which is provided with 48 slots and 4 poles. According to the single-layer short isometric winding of the 48-slot 4-pole three-phase asynchronous motor, the length of the end portion of the winding is shortened through changing of the pitches of the coils so as to shorten the total length of the coils and reduce stator resistance, and consequently copper consumption of the stator is reduced. Meanwhile, fifth subharmonics and seventh subharmonics severely affected in a magnetic field of the motor are significantly reduced, the phenomena of magnetic leakage are reduced, and consequently stray losses are lessened. Moreover, efficiency and performance of the motor are effectively improved, and compared with an existing single-layer winding, the wires are saved by about 15% and production efficiency is improved by 30%.

The invention relates to a dynamometer-based method for measuring and analyzing the efficiency of the electric motor of an electric bicycle. The method comprises the following steps: a, a measuring device is connected with the electric bicycle; b, the output voltage of a DC stabilized power supply equals to the rated voltage of the electric motor, a rolling handle is adjusted, and the maximum open state is maintained; c, after the output voltage of the DC stabilized power supply reaches 1.25 times the rated voltage, the corresponding output voltage is gradually reduced until the undervoltage protection starts, and a measurement result is recorded; d, a power loss curve graph is drawn; the output voltage of the DC stabilized power supply equals to the rated voltage of the electric motor until the electric motor reaches the rated output power; e, the DC resistance of the electric motor is measured to obtain copper loss; f, the power loss of the controller of the electric motor is obtained according to the input power, the output power, electric copper loss, electromechanical loss, armature iron loss and stray losses of the electric motor; g, and the efficiency of the electric motor is obtained. The method is simple, economical and practical, and has the advantages of high measuring accuracy and good applicability.

The invention relates to a method for ordering power by heat of a heat supply unit based on turbine energy balance. The method comprises the following steps that according to turbine energy balance, a mathematic model of the heating steam extraction flow and industrial steam extraction flow of the heat supply unit relative to active power is obtained; according to the mathematic model, the relational expression of the minimum load to the maximum load of the unit is determined; stray losses such as valve steam leakage, heat transfer and radiation losses existing in the steam turbine flow process are considered, parameters of the relational expression of the minimum load to the maximum load are recognized and corrected by means of the least square method to obtain a precise mathematic model; data obtained from a unit DCS is transmitted to a system master station, the minimum load value and the maximum load value of the unit are obtained and transmitted to a power grid dispatching control center; integration is performed on the relational expression of the minimum load to the maximum load, an expression of the minimum electric quantity and the maximum electric quantity relative to the heat supply amount relation is obtained, according to the heat supply amount of various power plant reported units, the minimum and maximum electric generation capacities are determined, and the basis is provided for formulating an electric quantity plan.

The invention relates to a 330kV-level three-phase three-winding high-impedance power auto-transformer with the function of on-load voltage regulation and belongs to the technical field of transformers. According to the technical scheme, a low-voltage winding (3), a common winding (4), a series winding (5) and a regulating winding (6) are sequentially and concentrically sleeved outside a three-phase five-pole core (2), and the low-voltage winding is serially connected with an electric reactor. An on-load tap changer is disposed at the end of a transformer oil tank. The electric reactor serially connected with the low-voltage winding is in a three-phase three-pole structure. Rectangular magnetic shields formed by stacked steel strips are disposed at upper and lower ends of a reactor winding (7), and the reactor winding is compressed with tie bolts made of low magnetism steel. The reactor winding is integrally connected with a core of the transformer through a clamp. The 330kV-level three-phase three-winding high-impedance power auto-transformer with the function of on-load voltage regulation has the advantages that short-circuit impedance voltage between high and low tension windings as well as between medium and low tension windings are achieved in such manner that the low-voltage winding is serially connected with the electric reactor, the transformer is small in size, light in weight, low in loss and the like, stray loss is reduced, and local overheating is avoided.

The invention discloses a motor rotor magnetic field sine method, a rotor structure, a motor and a compressor. According to the method, a plurality of magnetic line channels are arranged in the region between a permanent magnet of a motor rotor and the outer circle of an iron core, and the circumferential size of each magnetic force line channel is set, so that the magnetic fields of outer circles of the rotors of the magnetic force line channels can be distributed close to sine. The magnetic force line channels are arranged in the region between the outer circle of the iron core of a motor rotor and a permanent magnet, and the widths of the magnetic force line channels are set according to the sine function, so that the waveform of gap flux density inside the motor of the motor rotor structure can be optimized into a relatively ideal sine curve, and the gap flux density has less low-order harmonic quantity, so that stray loss, electromagnetic noise, vibration and other adverse influences caused by low-order harmonic quantity can be effectively reduced, and the comprehensive operation index of the motor can be promoted. Furthermore, the performance of a compressor and noise and vibration indexes can be improved.

The invention discloses a method for driving a high power high speed DC brushless motor controller. The method comprises the following steps of: driving a motor by adopting a pulse width modulation method, and sampling the position information of a motor rotor by adopting a Hall sensor in a pulse width modulation interval; detecting the regularity of the position information detected by the Hall sensor, detecting the rotating speed change rate of the motor, and ignoring a detection result if the position information of the Hall sensor is detected to exceed a set range; computing the rotating speed of a rotating model by utilizing periodic information obtained by the Hall sensor, and performing phase synchronization on the rotating model by utilizing separated position information obtainedby the Hall sensor to simulate the continuous position information of the motor. In the method, a sine wave driving scheme is adopted; the method has the advantages of low switching loss, low electromagnetic radiation, high efficiency, high bus voltage utilization rate and the like; and the rotating model has high stability, thereby achieving the high stability, low noise, low stray loss and highefficiency of the motor.