125results about How to "Improve output waveform quality" patented technology

The invention discloses a five-level self-balanced inverter based on a bridge switched capacitor module and relates to a multi-level inverter. The five-level self-balanced inverter is provided with the bridge switched capacitor module and two half-bridge circuits. The bridge switched capacitor module is provided with an H bridge and a switched capacitor module. The H bridge is provided with four high-frequency switches S1, S2, S3, and S4. The switched capacitor module is provided with a first capacitor C1a and a second capacitor C1b which are in series connection with a first capacitor network, a third capacitor C2a and a fourth capacitor C2b which are in series connection with a second capacitor network, and four full-controlled devices MOSFET switching tubes S1a, S1b, S2a, and S2b. The two half-bridge circuits are formed by four full-controlled devices MOSFET switching tubes S5, S6, S7, and S8. The five-level self-balanced inverter based on the bridge switched capacitor module may output five levels including 0, +-/2Ui, and +/-4Ui by controlling switch operating state, and achieves boosted output while outputting the multiple levels.

The invention discloses a control method of a hybrid-control cascaded multilevel inverter and a multilevel inverter. The controlling method comprises the following steps: obtaining output voltages of N groups of photovoltaic cells to get 1st, 2nd,..., ith,..., Nth output voltages; counting conduction angles theta1', theta2',..., thetai',...,thetaN' of the 1st, 2nd,..., ith,..., Nth output voltages; ceiling to obtain theta1, theta2, theta(i),..., theta(N); controlling the conductions of the 1st, 2nd,..., ith,..., Nth output voltages respectively by utilizing the conduction angles theta1, theta2, thetai,..., thetaN; obtaining step wave output voltages by utilizing a step wave algorithm; obtaining the output voltages of m groups of photovoltaic cells; utilizing an instantaneous value feedback algorithm to get instantaneous value feedback output voltages; and serially overlapping the step wave output voltages with the instantaneous value feedback output voltages to form a total output voltage, thus implementing the change from the DC (direct current) multilevel input into the AC (alternating current) level output. By using the scheme provided by the invention, the work frequency can be decreased, the conversion efficiency of the inverter is improved, the electromagnetic interference is reduced and the system structure is simplified.

The invention discloses a parallel variable frequency power supply for a high power and high voltage test, and belongs to the technical field of electric systems. The parallel variable frequency power supply comprises two or more parallel variable frequency power supply parts with current limiting reactors. The parallel variable frequency power supply solves the problem that a main variable frequency power supply controller decodes falsely due to the fact that the signal transmission quantity of optical fiber communication is large when two or more power supplies run in parallel; the parallel variable frequency power supply ensures that asynchronism of output voltage of the parallel variable frequency power supplies is controlled within 1 microsecond; the output synchronism of the variable frequency power supplies is improved; and circular current of output among the power supply parts is realized. In addition, as guard signals are arranged among a main variable frequency power supply and slave variable frequency power supplies, the deficiency in the prior art that when remedial operation cannot be conducted when the variable frequency power supplies fail is overcome.

The invention discloses an indirect matrix transformation type multi-phase multi-level permanent magnet motor system. The indirect matrix transformation type multi-phase multi-level permanent magnet motor system includes a double-stator multi-phase composite permanent magnet synchronous motor, wherein two independent five-phase three-level inverters supplies power for stator winding ports of the motor respectively; an independent controllable rectifier supplies power for each five-phase three-level inverter; the two controllable rectifiers can share one set of LC filter at the power grid side; the LC filter includes a three-phase grid-connected inductor and a three-phase filter capacitor which is connected with the three-phase grid-connected inductor in parallel; and the first five-phase three-level inverter and the second five-phase three-level inverter are respectively connected with the two stator winding ports of the double-stator multi-phase composite permanent magnet synchronous motor. The invention also discloses a control method of the indirect matrix transformation type multi-phase multi-level permanent magnet motor system. The indirect matrix transformation type multi-phase multi-level permanent magnet motor system and the control method thereof can significantly improve reliability, power density, torque smoothness and operation efficiency of the motor driving system, and can lay the foundation of solving the technical difficulty that a high capacity motor traction driving system requires compact designs, reliable operation and energy-efficient aspects.

The invention provides a control system for an all-digital single-pulse electroplating power supply, and relates to the technical field of an electronic circuit. The control system comprises an EEROM (electrically erasable read-only memory), a power amplifier board, a secondary temperature detection and protective module, a communication port, an analog amplifier, a PWM (pulse width modulation) signal drive transformer and a display module, wherein the EEROM is connected with a digital signal processing module and used for storing the working parameters of the power supply and storing the control parameters in power failure, the communication port is used for completing communication, the analog amplifier is used for amplifying the feedback voltage and a telecommunication signal, and the display module is used for a power supply state indicator lamp and a buzzer. The control system for the all-digital single-pulse electroplating power supply is high in pulse width precision, and the consistency of products in the metal surface processing and the product quality can be guaranteed.

The invention provides a circuit structure of a single-level single-phase large-step-up-ratio cascade connection voltage type convertor of a quasi impedance source. The circuit structure of the single-level single-phase large-step-up-ratio cascade connection voltage type convertor of the quasi impedance source is composed of an input direct-current power source or a single-phase alternating current power source, a high frequency combination modulation switch, a filter, a single-phase alternating current load or a direct-current load, wherein the input direct-current power source or the single-phase alternating current power source, the high frequency combination modulation switch, the filter, the single-phase alternating current load or the direct-current load are connected in a cascading mode in sequence. A large-step-up-ratio impedance network is connected between the input power source and the high frequency combination modulation switch. The large-step-up-ratio impedance network is formed by series connection of an energy storage inductor and n SLCC type two-port impedance network units, wherein the n SLCC type two-port impedance network units are the same and are connected in a cascading mode in sequence. The n is a natural number larger than one. Each SLCC type two-port impedance network unit is composed of a power diode or a four-quadrant power switch, an energy storage inductor and two energy storage capacitors. The high frequency combination modulation switch is composed of a two-quadrant power switch or a four-quadrant power switch. The convertor can effectively convert an unstable low-voltage direct current with a wide changing ranged or a single-phase alternating current into a stable and high-quality single-phase sinusoidal alternating current or direct current in a single-level mode and can be applied to occasions of electrical energy conversion with medium and small capacity.

The invention relates to a cascaded multi-mode photovoltaic grid-connected inverter and a modulation method thereof, belonging to the field of power conversion and new energy distributed grid-connected power generation. The modulation strategy can be adjusted and the working state of the switch can be adjusted to a nine-level, five-level or three-level mode according to the actual working condition, so as to optimize the quality of output waveform and reduce the overall loss. When the input power of the DC side is low, a nine-level or five-level output mode is adopted to improve the waveform quality of the grid-connection current and widen the grid-connection range. When the input power of the DC side is high, a three-level output mode is adopted to reduce the loss of the inverter and improve the efficiency of the system. Both the waveform quality of the current injected by the photovoltaic grid-connected inverter into the grid and the loss of the inverter are taken into account, whichis beneficial to improving the quality of the grid-connected power of the system and reducing the loss in the inverting process.

The invention discloses an ANPC five-level inverter and a model prediction control method thereof. The inverter includes three phases of bridge arms connected in parallel. Each phase of bridge arm includes eight IGBTs. Four IGBTs connected in series are connected with positive, negative and neutral points of a direct current bus, and the other four IGBTs connected in series are connected to outputof IGBT tubes one and three. An input end of each bridge arm is connected with a direct current voltage source. According to the ANPC five-level inverter and the model prediction control method thereof, novel model prediction control does not need to adjust PI parameters and positive and negative sequence separation as compared with traditional PI control methods, control is simple, the amount ofcalculation is greatly reduced, DSP realization is facilitated, a zero common mode voltage vector is selected for the leakage current problem existing in five-level photovoltaic grid-connected inverters, leakage currents can be completely eliminated, a redundant switch is selected for the neutral point potential imbalance problem existing in five-level ANPC inverters, neutral point potential balance control is realized, and flying capacitor equality control is realized. The inverter and the method can be applied to the field of renewable energy power generation such as photovoltaic power generation systems.

The invention provides submarine optical cable burial depth detection equipment. The submarine optical cable burial depth detection equipment comprises a transmitter, a submarine optical cable, a probe and a signal processing and displaying device. The transmitter is electrically connected with the submarine optical cable and outputs low-frequency sine waves to the submarine optical cable. The probe comprises a first coil, a second coil and a third coil, the first coil and the third coil are symmetrically arranged at the two ends of the probe, the second coil is located in the center of the probe, and the centers of the three coils are located on the same straight line. The second coil and the probe are coaxially arranged, and the axis of the first coil and the axis of the third coil are perpendicular to the axis of the probe. The probe wire moves in an area where a submarine optical cable to be detected is located. The first coil, the second coil and the third coil feed back measured induction electric signals to the signal processing and displaying device respectively. The signal processing and displaying device determines the route of the submarine optical cable and the distance between the probe and the submarine optical cable according to the three paths of induction electric signals. According to the invention, the burial depth of the submarine optical cable can be accurately determined.

The invention discloses a cascading type six-switch multilevel inverter. The cascading type six-switch multilevel inverter comprises multiple power units, wherein each power unit consists of a main switch group and a switch capacitor group, wherein the main switch group adopts a conventional full-bridge structure; the switch capacitor group comprises a switch capacitor, two power switch tubes and three uncontrollable diodes; a first bridge arm midpoint and a second bridge arm midpoint of each main switch group are used as output positive and negative ends of each power unit; and the inverter comprises the multiple power units in a cascading manner in sequence. According to the inverter, each power unit can generate five-level output voltage; when an output voltage of the same number of levels is realized, the number of the power switching devices is greatly reduced; the complexity of the device is lowered as well; and in addition, the cascading type six-switch multilevel inverter has the characteristics of high inversion efficiency and high reliability.

The invention relates to a clamping-type three-phase voltage-source type inverter and a control method thereof and belongs to the technical field of three-phase voltage-source type inverters. The clamping-type three-phase voltage-source type inverter comprises a direct-current power source, a three-phase three-level inverter bridge, a three-phase LC filter and a three-phase load. In order to control output voltage waveforms, a mathematical model of the three-level inverter is established, an instantaneous value control system of the output voltage is put forward, a scheme combining a fundamental-wave disturbance instantaneous value controlled internal model with a harmonic disturbance repetitive controlled internal model under rotating coordinates is adopted, disturbance of the internal models is realized to acquire voltage output waveforms high in quality by adopting structural controllers in parallel, and a control method for fixing resultant vectors is adopted with an aim to solve problems about voltage jump of the three-level inverter and neutral voltage potential balance. The clamping-type three-phase voltage-source type inverter is ideal in comprehensive output voltage performance and good in output waveform quality, and meanwhile, the problems about voltage jump and neutral voltage potential balance are solved.

The invention discloses a single carrier PWM method for achieving a stacked carrier effect and belongs to the technical field of electric system control. According to the technical scheme, a reference carrier signal and a modulating wave are generated at first; an instantaneous value of the modulating wave in each moment is divided by a reference carrier amplitude value to obtain a round number, the serial number of the carrier which has an intersection point with the modulating wave during equivalent adopting of stacked carriers is obtained, then instantaneous values of the carriers are made to be equivalent through longitudinal horizontal movement of a reference carrier and are compared with the instantaneous value of the modulating wave, and an output signal is obtained. According to the single carrier PWM method, the modulating effect of the stacked carriers with any number can be achieved conveniently with only one reference carrier, only one time of comparison operation between the carrier and the modulating wave needs to be executed for every moment, computation delay of a controller is effectively reduced, and output waveform quality and the response speed of a device are improved.

The invention discloses a small and efficient high-power solid-state modulator and belongs to the technical field of pulse power. The modulator comprises a solid-state modulator component and a pulse transformer (T), wherein the solid-state modulator component comprises a direct-current power supply (E1), an energy storage capacitor (C1) and a solid-state switch (V1). The direct-current power supply (E1) is used for charging the energy storage capacitor (C1). Output pulses of the modulator are obtained through the pulse transformer (T) after the energy storage capacitor (C1), the solid-state switch (V1) and the pulse transformer (T) form a discharge circuit. According to the small and efficient high-power solid-state modulator, the single solid-state switch is used, the equalization voltage and the connection consistency of the solid-state switch are not required to be considered, the voltage is low, insulation design can be achieved easily, the output waveform quality of the modulator is greatly improved, the circuit topological structure is simple, the size is small, the efficiency is high, modularization can be achieved easily, and the modulator is applicable to various platforms.

The invention relates to an axial leading-out double-pole-plate coiling pulse formation line, and belongs to the technical field of pulse power. A pulse formation line body is formed by coiling two pole plates and two medium layers in an Archimedes spiral manner, the high-voltage pole plate, inner-side insulating media, the low-voltage pole plate and outer-side insulating media are arranged successively from inside to outside, and the positions of the high-voltage pole plate and the low-voltage pole plate can be interchanged; and the high-voltage pole plate, inner-side insulating media, low-voltage pole plate and outer-side insulating media are coiled for n rounds in the Archimedes spiral manner, the first round of the high-voltage pole plate and the first round of the low-voltage pole plate are led out in the axial two sides via a high-voltage leading-out foil and a low-voltage leading-out foil respectively, and the pulse formation line composed of an axial leading-out structure and n-a rounds of complete band-shaped wires is formed. The coiling pulse formation line is high in quality of output waveforms, and is simpler in structure compared with a three-pole-plate coiling band-shaped line.