55results about How to "Avoid harmonics" patented technology

The invention relates to a speed-adjusting-type permanent-magnet drive system, comprising a conductor rotor (a first rotor), a magnetic rotor (a second rotor) component and a lead screw regulator, wherein the conductor rotor (the first rotor) is arranged on an input shaft; the magnetic rotor (the second rotor) is arranged on an output shaft; the conductor rotor comprises a disk-shaped steel frame and a copper conducting ring; the surface of a steel plate is provided with the copper conducting ring; the opposite surfaces of a permanent-magnet rotor and the conductor rotor are embedded with permanent magnets; the gap of the opposite surfaces of the conductor rotor and the permanent-magnet rotor can adjust an axial air clearance; and the conductor rotor and the permanent-magnet rotor are coupled by the magnetic force. When the conductor rotor rotates, the permanent-magnet rotor also rotates along the same direction with the conductor rotor due to the coupling action of the magnetic force; the conductor rotor (the first rotor) is fixedly connected with the input shaft; the permanent-magnet rotor (the second rotor) is connected with the output shaft by a shaft section; the regulator is arranged on the shaft section; and the air clearance between the disk surfaces of the two rotors can be adjusted by the regulator, thus changing the torque and the rotating speed and achieving the purpose of speed adjustment.

The invention relates to a control method for a photovoltaic grid-connected inverter on the basis of back-stepping sliding-mode control. The control method is technically characterized in that direct current voltage Udc of a photovoltaic side bus is collected, a mathematical model of a photovoltaic grid-connected single-phase voltage full-bridge inverter is set up, a tracking error of a control variable uac is set, a back-stepping sliding-mode control model of the photovoltaic grid-connected single-phase voltage full-bridge inverter is set up, and the single-phase photovoltaic grid-connected inverter is controlled according to the mathematical model and the back-stepping sliding-mode control model of the photovoltaic grid-connected single-phase voltage full-bridge inverter. The control method is reasonable in design, a back-stepping method and a sliding-mode control method are combined, the stable state and the dynamic property are good, and the control method is suitable for linear and non-linear loads and adapts to engineering application reality, provides a new thought for the inverter control system design and has the good engineering application prospect.

A transceiver having an RF receiver, in particular VHF receiver, with digital signal processing in a digital part. The transceiver having an input part, at least one mixer and an intermediate frequency/baseband processing device, having a local channel oscillator, to which a first phase locked loop with a phase discriminator and an adjustable first frequency converter are assigned, and having a reference oscillator for the phase locked loop and the control clock of the digital signal processing device, in which, in order to acquire the control clock, a digital clock synthesizer is provided to which an output signal of the reference oscillator is supplied, and a control signal is supplied by the digital part in the form of a digital tuning word, the frequency of the reference oscillator being selected such that its order of magnitude is at least equal to the bandwidth of one or more of the reception bands used, and none of its harmonics occur in a reception channel.

An electronic ballast for a discharge lamp has a compact arrangement of electric parts. The ballast includes an AC-DC converter and an inverter giving a high frequency output voltage for operating the lamp. The inverter includes switching elements, a control circuit, and an output transformer for connection with the lamp. A single circuit board mounts the electric parts forming the converter and the inverter. The circuit board is accommodated within a tubular casing together with a dielectric sheet which is provided for insulating the circuit board as well as the electric parts from the casing. The output transformer is mounted on a top surface of the circuit board together with some of the other electric parts. The ballast includes chip components forming a detection circuit for lamp condition, and the circuit board mounts the chip components on a bottom surface at a location immediately opposite of the output transformer.

A high-frequency module is connected to a switch port and a switch IC including an antenna connection port and a plurality of switch ports. The high-frequency module includes a signal path that outputs transmitting signals having a predetermined frequency band to the switch IC, a module port connected to the signal path and to which a duplexer and a transmitter circuit are connected, and a harmonic branch circuit that is provided on the signal path and allows a harmonic of the transmitting signal to escape to ground.

The invention provides a novel rotating rectifier with a fault monitoring function, and relates to rotating rectifying systems. The invention aims at solving the problems that an existing rectifier is low in output power of an alternating-current exciter and high in harmonic component, a rotating rectifying controller cannot be timely started and a system fault exists. The novel rotating rectifier with the fault monitoring function comprises a three-phase triple voltage rectifying circuit, an alternating-current exciter, a rotating bridge rectifier module based on VIENNA, a start power module, a start resistor, a rotating rectifying controller, a synchronous electric exciter set, a fault detection module, a wireless communication device, a first wireless transceiving device, a second wireless transceiving device and an external monitoring module. According to the novel rotating rectifier with the fault monitoring function, a neutral-point potential balance method of injecting zero-sequence voltages is adopted, zero-sequence voltages VZ(+) and VZ(-) are injected into a three-phase reference voltage at different moments, and the problem is solved that two capacitor voltages of a direct current busbar are not balanced.

The invention discloses a power supply system used for a suspension control system. The system comprises a suspension power supply and a control power supply, wherein the two poles of the suspension power supply are connected with a suspension chopper circuit so as to be used for supplying power for the suspension chopper circuit; and the two poles of the control power supply are respectively with the two poles of a plurality of low-voltage direct-current power supplies so as to be used for supplying power for the low-voltage direct current power supplies. According to the power supply system, the condition that the suspension power supply can be impacted due to the work of the suspension chopper circuit when a train is in suspension can be avoided, so that the low-voltage direct current power supplies can be prevented from being interfered, the low-voltage direct current power supplies can output current and voltage stably, the normal work of a suspension controller, various suspension parameter measuring sensors, a driver of a chopper power tube, and the like can be ensured, further, the normal work of the suspension control system is ensured, and the safety of the suspension control system is improved.

The invention relates to an LED (light-emitting diode) wall wash lamp, which comprises a lamp body, a light-transmitting plate and two hinge pressing bars, wherein the light-transmitting plate is arranged on a light-emitting opening at the top of the lamp body; the two hinge pressing bars are symmetrically arranged at the two sides of the lamp body, and are distributed along the length direction of the lamp body; circular grooves are arranged near outside of the top of the lamp body; the circular grooves are distributed along the length direction of the lamp body; ribs which are distributed along the length direction are arranged near the inner side surface of a neck part of the hinge pressing bar; the ribs are in a cylindrical shape, and are in running fit with the circular grooves; the tail end extending inwards at the top of each hinge pressing bar is suitable for compressing the edge of the light-transmitting plate; the lower end part of each hinge pressing bar is provided with a bolt used for controlling the tail end to compress the light-transmitting plate; under the action of the bolt, the lower end part of each hinge pressing bar is suitable for the side away from the lamp body; and the ribs rotate in the circular grooves, so that the light-transmitting plate is compressed by the tail end.

The invention discloses a new energy power station dynamic reactive power compensation equipment application method. The improved content is as follows: (1) the dynamic reactive power compensation equipment is connected onto a low voltage-side bus of a three-winding boost transformer, the middle voltage side of the three-winding boost transformer is connected with gathered new energy electric power, and the two are isolated via the transformer; (2) voltage at the high voltage side of the new energy power station serves as reactive power needed by a calculation system for calculating reference voltage and control target voltage; and (3) a novel electronic current voltage combined transformer is applied to a measurement control system for the dynamic reactive power compensation equipment. In view of problems of poor operation stability of the new energy power station and disqualified electric power quality, a dynamic reactive power compensation configuration technology which can be applied to grid-connected power generation of the new energy power station and meet grid requirements is brought forward, a dynamic reactive power compensation equipment mounting site is changed, the new energy collecting system and the reactive power compensation equipment can be effectively isolated, the problems of operation stability of the new energy power station compensation equipment and electric power quality can be solved, and operation stability of the reactive power compensation equipment is improved.

The invention discloses a sampling clock generation circuit and an analog-digital converter and belongs to the digital signal processing field. The sampling clock generation circuit comprises a variable-resistance circuit, a NOT gate type circuit and a capacitor, the input end of the NOT gate type circuit receives pulse signals of which the period is T, the output end of the NOT gate type circuit is connected with one end of the capacitor, the other end of the capacitor is connected with the ground, the power supply end of the NOT gate type circuit is connected with a power supply, the ground end of the NOT gate type circuit is connected with one end of the variable-resistance circuit, and the other end of the variable-resistance circuit is connected with the ground; the NOT gate type circuit is used for outputting low level when the pulse signal has high level and outputting high level when the pulse signal has low level; the variable-resistance circuit is used for regularly changing the resistance according to a time length T, the resistance change period is n*T, the resistance is different after each change in each period, and n is an integer larger than or equal to 2. The sampling clock generation circuit and the analog-digital converter enable the conversion accuracy of the ADC to be improved.

The present invention discloses a DC feedback type DC electronic load for locomotive power supply tests. The DC feedback type DC electronic load comprises a main circuit and a control circuit, wherein the main circuit is cascaded by a boost chopping circuit and a phase-shifted full-bridge circuit; and the control circuit is composed of a digital signal processing unit DSP and a logic control unit CPLD, is connected with an upper computer through a CAN communication circuit, is connected with a contactor control coil and an auxiliary coil through a switching signal processing circuit, is connected with voltage and current sensors through an analog signal processing circuit, controls the on-off of an IGBT in the main circuit through an IGBT driving module, and achieves the required load simulation and energy feedback functions. The DC feedback type DC electronic load allows tested energy to be recycled, saves a series of conversion links such as rectification and inversion when compared with a method of feeding the energy back to an AC power grid, makes the control method simpler, and reduces cost.

The invention discloses a voltage modulation method and device. The voltage modulation method comprises the following steps: determining that SVPWM is in an overmodulation region; under the conditionthat a phase angle of the reference voltage is kept unchanged, correcting the amplitude of the reference voltage, so that a reference voltage vector is located in a hexagonal coverage area of a voltage space vector plane; obtaining a corrected three-phase modulation wave, and then carrying out space vector pulse width modulation on the corrected three-phase modulation wave. Since only the reference voltage amplitude is corrected once, the modulation implementation mode is simple. Moreover, the corrected reference voltage vectors are all located in the hexagonal coverage area of the voltage space vector plane. The phase angle of the reference voltage in the hexagonal coverage area of the voltage space vector plane is linearly changed; therefore, the phase angle of the reference voltage doesnot change suddenly, harmonic waves generated by voltage distortion are avoided, the problem that motor loss is increased due to the voltage harmonic waves is effectively solved, and the power performance of the whole vehicle in a high-speed running state is improved.

The invention relates to an electrolyser applicable to titanium cathode plates. The electrolyser comprises a electrolyser body, wherein ion exchange membranes are arranged in the electrolyser body and are used for partitioning the electrolyser body into anode chambers and cathode chambers, and a discharging funnel is further arranged at the bottom of the electrolyser body and is connected with the cathode chambers; the titanium cathode plates are arranged between the anode chambers and the cathode chambers; the discharging funnel is connected with a liquid outlet pipe so as to discharge electrolysis waste liquid; and a collection bin which is suitable for collecting precipitated metal is arranged at the bottom of the discharging funnel, and the entrance of the collection bin is connected with the bottom of the discharging funnel. According to the electrolyser, the precipitated metal is collected by the collection bin, so that the precipitated metal can all be collected, the electrolysis operation and the operation collection are separated from each other and are independent from each other, and the electrolysis efficiency is increased.

The invention relates to a high-efficiency discharging feedback type battery charging power source, which comprises a main control module and an isolation transformer, wherein the isolation transformer is connected with a three-phase power supply end, secondary sides of the isolation transformer are connected by a star and a triangle, the output ends of the star and the triangle are respectively connected with two input ends of a 12-phase rectifier through two interlocking contactors, the output ends of the 12-phase rectifier are respectively connected through corresponding filtering inductances to form a common direct current bus, the common direct current bus is connected with a plurality of charging and discharging circuits and a sine wave inverter in parallel, each charging and discharging circuit comprises a plurality of charging subcircuits and discharging subcircuits for controlling the charging and discharging of the corresponding storage battery, the interior of each charging subcircuit or each discharging subcircuit comprises a power measuring unit, a main control module is connected with the corresponding power measuring unit to collect the charging power of each charging subcircuit and the discharging power of each discharging subcircuit, and the sine wave inverter is controlled to invert the bus voltage back to an alternating current power grid when the total discharging power is greater than the total charging power.

The invention discloses a high-voltage cabinet output power adjusting circuit which comprises a frequency acquisition circuit, a feedback compensation circuit and a voltage conversion circuit. The frequency acquisition circuit uses a power collector J1 with the model of AD8318 to acquire a power signal of the voltage output end of a high-voltage cabinet, the feedback compensation circuit uses thediodes D5 to D8 and an operational amplifier AR1 to form a composite circuit to carry out amplitude limiting-amplification-amplitude limiting adjustment on a signal, meanwhile, uses a triode Q1, a triode Q3 and a capacitor C8 to form a constant-current circuit to input the signal into the voltage conversion circuit in a constant-current manner and uses a silicon controlled rectifier VTL1 and a voltage stabilizing tube D11 to form an abnormal signal detection circuit to screen out the abnormal signals in the output signals of the constant current circuit, and finally the voltage conversion circuit is composed of a variable resistor R16, an operational amplifier AR5 and a capacitor C9 to convert a current signal into a voltage signal to output, so that the power of the voltage output end ofthe high-voltage cabinet can be monitored in real time, and meanwhile is converted into a compensation signal of the output power of the high-voltage cabinet.

The invention belongs to the technical field of an intelligent power grid and discloses a method and a device for eliminating harmonic wave of a photovoltaic grid connected charging system. The method particularly comprises the following steps: acquiring the phase voltage of any phase of a three-phase alternating current (AC) power grid; acquiring voltage phase information according to the phase voltage; acquiring the voltage and the current of a photovoltaic battery; acquiring active instruction current corresponding to three phases respectively according to phase locking voltage phase, the voltage of the photovoltaic battery and the current of the photovoltaic battery; acquiring AC side charging current corresponding to the three phases respectively; obtaining harmonic compensation instruction current of each phase according to the phase locking voltage phase and the AC side charging current; combining the harmonic compensation instruction current of each phase with the active instruction current to obtain output instruction current; and outputting the output instruction current to an electric automobile, so that the electric automobile can be charged, and influence on the performance of the three-phase AC power grid caused by the situation that the harmonic wave generated by charging the electric automobile enters the three-phase AC power grid is avoided.

The invention relates to a motor comprising a stator, a stator winding, a rotor, a rotor winding, a shaft and relative positioning parts. On the action principle the motor acts according to the change of magnetic field size and direction around the conductor and does not need a plurality of trunking structures on the stator, further all the sections of the winding conductor generates electromagnetic induction action, that is hundred-percent effective. Because the stator winding is independent to each other and the stacking and pressing between the multi-trunking and the multi-winding does not exist, not only the withstand voltage obstacle is overcome, but also solves the problem that joints exists between the multiple windings and the multiple circles, reduces many working procedures and cost and saves energy. The motor of the invention can be an ac motor, a dc motor and motors for special use.

The invention provides a driving method and circuit for a permanent magnet synchronous motor. The driving circuit for the permanent magnet synchronous motor comprises a driving control module, a current detection module, a power driving module and a magnetic pole position detection module; the driving control module comprises a speed solving unit, a speed control unit, a current control unit, a decoupling variation unit and a sine wave control unit; the current detection module comprises a current detection circuit, a signal conditioning circuit and an analog-digital conversion circuit; the magnetic pole position detection module comprises a magnetic pole position detection sensor and a signal conditioning circuit; through PLL/PID dual-mode control, the problem that the traditional PID controlled motor has the phenomenon of control delay due to time draft in stability can be solved and the stability of the speed of the motor can be improved further.

The invention discloses a segmented controllable series reactor device and a distribution line voltage control method thereof. The segmented controllable series reactor device comprises a reactor andK switches, wherein the reactor is provided with k-1 points to divide the reactor into K parts; and one switch is connected in parallel with one part of the reactor, and the K switches are connected in series. The K switches are connected in series and then are connected with the reactor in parallel, the inductance values of the reactors connected with the switches are different, the inductive reactance value of the reactor can be divided into 2k grades by controlling the on-off of each switch, and the inductive reactance value is changed by directly utilizing the switches, so that a controllable thyristor is omitted, the loss can be reduced, the efficiency can be improved, and harmonic waves in voltage at two ends of the reactor and flowing current can be avoided. The device is matched with a distributed photovoltaic inverter with rapid and continuous reactive power regulation capability, so that the problem of voltage rise suppression in the photovoltaic power distribution network can be better solved.