14results about How to "Reduce harmonic components" patented technology

This application discloses a grid-connected inverter control method based on a notch filter phase-locked loop (PLL) for weak grid conditions. The method first designs a notch filter with adjustable notch depth and bandwidth, setting its notch frequency to the grid power frequency. It then acquires the three-phase voltage at the grid connection point, subtracts the voltage after notching, and extracts the power frequency component of the three-phase voltage. The power frequency component is phase-locked in a synchronous reference frame to obtain the modulation wave phase signal. The inverter output voltage and current are acquired, and active and reactive power are calculated. A dual closed-loop control circuit with an outer power loop and an inner current loop is constructed, outputting the modulation wave voltage amplitude signal. Finally, the modulation wave phase signal and amplitude signal are combined to generate a pulse modulation wave signal. Thus, this invention can accurately lock the grid phase when the weak grid voltage contains harmonics and DC components, effectively improving the stable grid-connected operation capability of the grid-connected inverter under large disturbances.

The present invention discloses a control method for a motor controller, comprising: cutting the full speed range of the motor controller into several speed intervals, and cutting each speed interval into several random speed intervals; obtaining the current speed of the motor controller, and determining which random speed interval the current speed falls into; performing random number calculation processing on the random speed interval in which the current speed falls, and generating a random switching frequency for the switch control of the motor controller; obtaining the current current value and the current electrical angle value of the motor controller, and generating an SVPWM pulse control signal; limiting the safe dead time of the motor controller, and outputting the SVPWM pulse control signal according to the limiting processing result. A control device for realizing the control method of the motor controller is also disclosed. The present invention widens the frequency conversion range of the motor controller, improves the output efficiency, improves the vehicle endurance, and improves the NVH index.

The invention provides a three-phase motor phase current sampling processing method, a three-phase motor control method and a three-phase motor, and the three-phase motor phase current sampling processing method comprises the steps: obtaining the on-off moments of at least a part of semiconductor switch tubes in a three-phase full-bridge inverter circuit in a first carrier period and a second carrier period, wherein the first carrier wave period and the second carrier wave period are two adjacent PWM carrier wave periods; determining a sampling moment according to the on-off moments of at least part of the semiconductor switch tubes in the first carrier period and the second carrier period and the time length Tsamp required by sampling; starting sampling on conduction voltage drop values of at least part of lower bridge arm semiconductor switch tubes of the three-phase full-bridge inverter circuit at a sampling moment; and calculating the current value of each phase of the three-phase motor according to the conduction voltage drop values of at least part of the lower bridge arm semiconductor switch tubes. According to the three-phase motor phase current sampling processing method provided by the embodiment of the invention, the technical problem that the three-phase motor phase current sampling is inconvenient and inaccurate in the prior art is solved.

The invention discloses a multi-level PT type wireless power transmission system, and the system comprises a primary loop which comprises a DC power supply, a three-level inverter, a primary resonant capacitor, and a transmitting coil; the secondary loop comprises a secondary resonant capacitor, a receiving coil, a rectifying circuit, a filter capacitor and a load; the transmitting coil and the receiving coil realize energy transmission of the primary side loop and the secondary side loop; the coupling model gain rate # imgabs0 # of the multi-level PT type wireless power transmission system is cos (alpha / 2) times of that of a full-bridge inversion PT symmetric WPT system. The introduced three-level inverter generates three-level voltage, and harmonic components of the three-level voltage are fewer, so that the voltage utilization rate is improved, and meanwhile, the device stress borne by an inverter switching tube is reduced; digital control is introduced, the duty ratio is adjustable, and compared with a traditional PT type WPT system with a single transmitting coil and a single receiving coil, more advantages are achieved.

The utility model belongs to the technical field of artificial heart-left ventricle auxiliary circulation equipment, and particularly discloses an LVAD motor stator system, which comprises an outer stator, an inner stator and a winding arranged between the outer stator and the inner stator, the inner stator is formed by stacking a plurality of silicon steel ring sheets, an axial modulation groove is arranged along the circumferential direction of the inner side of the inner stator, and the inner side of the inner stator is connected with the winding. According to the utility model, the modulation grooves are arranged in the inner stator, so that the harmonic amplitude is reduced, and the fluctuation of the torque is reduced. The utility model also discloses a motor which is filled with epoxy resin, so that the relative positions of related parts are ensured, the coaxiality and dynamic balance of the related parts are ensured, the motor is stable in high-speed operation, the vibration can be reduced, the motor has relatively good biological safety, relatively high heat conductivity coefficient and chemical stability, and the heat is quickly dissipated when the motor is in high-speed operation. The device is suitable for being placed in a human body.

The utility model belongs to the technical field of industrial automation measurement and control, and discloses an isolation type thermal resistance temperature signal conditioning system, which comprises a constant current source circuit; an amplification circuit; a VF conversion circuit; an FV conversion circuit; a low-pass filter circuit; and a linearization circuit. According to the utility model, the instrument amplifier with a high common-mode rejection ratio is adopted to suppress common-mode noise, the hardware filtering design is optimized, multi-stage low-pass filtering is adopted to eliminate power frequency harmonic waves, and a mirror image constant current source is adopted to enhance the stability; a reverse protection circuit is added in a double-TVS diode clamping mode, and a wide input voltage range power supply chip is properly selected. VF / FV conversion time sequence control is adopted, a scheme of dynamically adjusting cut-off frequency is adopted, filtering parameters are automatically switched according to a signal variable rate, and noise suppression and response speed are balanced.

The utility model relates to a zero-crossing trigger circuit of a bidirectional thyristor and a circuit board. The circuit comprises a switching control circuit and a switch driving circuit. The switching control circuit is used for detecting the alternating current zero-crossing state of the power system, the input end receives a switching signal, and the output end is connected with the input end of the switch driving circuit so as to control the input end of the switch driving circuit to generate an opening and closing signal when the switching signal is received and the alternating current crosses zero. The switch driving circuit comprises a control resistor, a first diode and a second diode which are connected in series, the first diode and the second diode which are reversely arranged are respectively connected with a sixth resistor and a seventh resistor in parallel, the series starting end serves as an output end and is connected with the main electrode of the bidirectional thyristor, and two ends of the control resistor are two sides of one group of input ends. The control electrode of the first silicon controlled rectifier of the bidirectional thyristor is connected with one side of the input end of the switch driving circuit close to the anode of the first silicon controlled rectifier, and the control electrode of the second silicon controlled rectifier is connected with the other side of the input end. Current impact at the moment of on-off of the bidirectional thyristor can be reduced.

The invention belongs to the technical field of nuclear power, and particularly relates to a high-voltage frequency converter harmonic control method and a filter. According to the method, the harmonic component in the output voltage of the frequency converter can be effectively reduced. According to the method disclosed by the invention, a relatively high fundamental frequency is obtained through modulation, and the voltage utilization rate is improved, so that the torque ripple of the motor is remarkably reduced. Under the same switching frequency, the method disclosed by the invention can generate the optimal output waveform. While the waveform quality is ensured, the switching frequency and the switching loss are reduced, and the overall efficiency of the system is improved.

The invention provides a rotor structure and a motor. The rotor structure comprises a rotor body and a plurality of magnetic bodies. The rotor body comprises a rotor yoke part and a plurality of rotor salient poles, the rotor salient poles are arranged on the outer circumferential surface of the rotor yoke part, and the plurality of rotor salient poles are arranged at intervals along the circumferential direction of the rotor yoke part; a mounting groove is formed between every two adjacent rotor salient poles; the magnetic bodies are arranged in the mounting grooves, and the plurality of magnetic bodies and the plurality of rotor salient poles are alternately arranged; grooves are formed in the side faces, making contact with the magnetic bodies, of the rotor salient poles. The motor comprises the rotor structure. The grooves are formed in the side faces, making contact with the magnetic bodies, of the salient poles of the rotor, magnetic leakage can be reduced, the sine degree of air gap flux density can be improved, the use amount of the magnetic bodies is reduced, meanwhile, counter electromotive force is effectively improved, the harmonic content of the counter electromotive force is reduced, and the operation performance of the motor can be improved, such as torque pulsation and noise reduction.

The utility model discloses a rotor assembly and a motor, and relates to the technical field of motors, the rotor assembly comprises a rotor yoke, a plurality of radial magnetic shoes and a plurality of circumferential magnetic shoes, and the rotor yoke is configured to be annular and rotates around a rotation axis; the plurality of radial magnetic shoes are connected to the inner side of the rotor yoke and configured to be magnetized in the radial direction of the rotating axis, and the plurality of radial magnetic shoes are arranged at intervals in the circumferential direction of the rotating axis; the plurality of circumferential magnetic shoes are connected to the inner side of the rotor yoke and configured to be magnetized in the circumferential direction of the rotating axis, and the plurality of circumferential magnetic shoes are located between every two adjacent radial magnetic shoes respectively; one side surface, facing the rotating axis, of each radial magnetic shoe comprises a first arc surface, and a first surface and a second surface which are connected to the two sides of the first arc surface in the circumferential direction, the distance between the first surface and the rotating axis is gradually increased in the direction away from the first arc surface, and the distance between the second surface and the rotating axis is gradually increased in the direction away from the first arc surface. The rotor assembly of the utility model can enhance the electromagnetic performance and improve the mute effect.

The utility model discloses a motor and a household electrical appliance, the motor comprises a rotor assembly and a stator assembly, the rotor assembly comprises a plurality of outer iron core units and a plurality of permanent magnets, the projection of the outer contour of each outer iron core unit comprises a second arc-shaped section, a first arc-shaped section and a fifth arc-shaped section which are connected in sequence on a projection plane perpendicular to a rotation axis, in the direction away from the first arc-shaped section, the distance between the second arc-shaped section and the rotating axis is decreased progressively, and the distance between the fifth arc-shaped section and the rotating axis is decreased progressively; the stator core comprises a plurality of stator units arranged in the circumferential direction, each stator unit comprises a yoke part, a tooth part and a shoe part, the yoke parts and the shoe parts are connected to the two radial ends of the teeth respectively, the radial outer wall faces and the radial inner wall faces of the yoke parts are parallel planes, every two adjacent yoke parts are connected, and a winding groove is defined between every two adjacent stator units. A groove opening of the winding groove is defined between every two adjacent shoe parts. The motor provided by the utility model can reduce harmonic components in an air-gap magnetic field, and reduce vibration and noise.

The application discloses a low-tooth-groove primary permanent magnet linear motor and belongs to the technical field of motors. The application aims at the problem of high tooth groove force of the primary permanent magnet linear motor. The primary permanent magnet linear motor comprises a primary and a secondary, the primary comprises a primary iron core, an armature winding and permanent magnets, the armature winding is wound on the armature tooth of the primary iron core, the armature winding is composed of concentrated windings, the tooth top of the armature tooth is processed with a plurality of unequal-width split teeth to form an odd number of split tooth grooves, the permanent magnets are embedded in the split tooth grooves, the permanent magnet in the middle split tooth groove is higher than the permanent magnets in the split tooth grooves on the two sides, and the plurality of permanent magnets form a non-uniform air gap magnetic field between the primary and the secondary. The application is suitable for high-precision direct drive motion control occasions.

The invention discloses a transmitter and a radar. The transmitter comprises a signal transmitting link and a compensation unit. Wherein the signal transmitting link comprises a first signal generator used for generating a baseband signal; the second signal generator is used for generating a local oscillator signal; the radio frequency transmitting circuit is connected with the first signal generator and the second signal generator and is used for outputting a radio frequency signal for radar detection by utilizing the baseband signal and the local oscillator signal; and the compensation unit is used for inputting the generated offset signal to a signal transmitting link so as to offset the harmonic signal in the radio frequency signal.

The invention relates to the technical field of motor stator windings, in particular to a semicircular externally-wound alternating current electronic stator winding which comprises a stator core, a plurality of winding grooves are evenly formed in the stator core in the circumferential direction, winding coils are evenly wound on the winding grooves, and the winding coils are wound from inside to outside along the axis of the stator core. The stator core is further connected with a PG plate, the PG plate and the stator core are coaxially arranged, and the diameter of the PG plate is the same as that of the stator core. According to the invention, the anti-interference performance and integrity of the stator winding are improved.