7results about How to "Reduce Harmonic Pollution" patented technology

This invention discloses a phase-shifted full-bridge plasma power supply based on all SiC devices, belonging to the field of special power supply technology. It includes: a rectifier unit with a power factor correction circuit; an inverter unit containing a phase-shifted full-bridge topology composed of SiC power devices and an energy storage inductor, achieving zero-voltage switching through phase-shift control; a transformer unit; an output unit including an output filter capacitor; and a control unit that uses an incremental PID algorithm to generate phase-shift control signals. This invention analyzes the differences in zero-voltage switching between the leading and lagging bridge arms, utilizes the low output capacitance characteristics and dynamic dead-time adjustment of SiC devices, broadens the soft-switching range under light loads, effectively reduces output current ripple, and improves dynamic response speed and overall efficiency.

The invention relates to the technical field of Vienna rectifiers, in particular to a control method for improving harmonic power grid input adaptability of a Vienna rectifier, which comprises the following steps of: performing coordinate transformation on acquired three-phase power grid voltage and input current to obtain voltage and current signals under a fundamental wave rotating coordinate system, extracting a fundamental wave current error signal, and calculating the harmonic power grid input adaptability of the Vienna rectifier; the method comprises the following steps: acquiring a current error component of each harmonic, converting the current error component into a rotating coordinate system corresponding to each specified harmonic to obtain the current error component of each harmonic, and in each harmonic rotating coordinate system, independently controlling the current error component of the corresponding harmonic by adopting a proportional-integral controller to generate a control voltage component of each harmonic; inversely transforming the control voltage component of each harmonic to a fundamental wave rotating coordinate system, and superposing to form a total harmonic compensation voltage; according to the invention, by adopting the control method of combining the self-adaptive loop parameters with the bus lifting strategy, the adaptability of the input current of the rectifier along with the power grid voltage under the harmonic power grid voltage is enhanced, so that the problem of overcurrent of the rectifier under different working conditions is avoided.

The application belongs to the technical field of power electronics, and discloses an optimal carrier modulation method and system considering oscillation and unbalanced midpoint voltage. The method obtains normalized sinusoidal waves of phase A, phase B and phase C according to a three-phase normalization formula of a SPWM modulation strategy of a three-level Vienna rectifier; calculates a modulation signal correction variable and an unbalanced coefficient of a midpoint voltage; calculates a zero sequence voltage u z.ICB considering oscillation and unbalanced midpoint voltage, and injects the zero sequence voltage into the three-phase normalized sinusoidal waves to obtain intermittent modulation waves of the three-level Vienna rectifier of phase A, phase B and phase C considering oscillation and unbalanced midpoint voltage. The application can greatly reduce switching loss and improve the efficiency of the converter under the working condition of oscillation and unbalanced midpoint voltage, and can suppress low-frequency harmonics and eliminate current zero-crossing distortion. The application does not need sector judgment and only needs to inject a zero sequence component, and is simple and convenient to implement.

This application provides a driving circuit and related equipment. The driving circuit includes a Vienna circuit, an MCU, and a step-down circuit. The first signal output terminal of the MCU is connected to the control terminal of the Vienna circuit, and the second signal output terminal is connected to the control terminal of the step-down circuit. The input terminal of the Vienna circuit is connected to a three-phase AC power supply, and its output terminal is connected to both the input terminal of the step-down circuit and the compressor via a DC bus. The output terminal of the step-down circuit is connected to a fan. The MCU sends a first control signal to the Vienna circuit to control its voltage conversion process, and simultaneously sends a second control signal to the step-down circuit to control its step-down processing of the input DC voltage, ultimately realizing the adaptation of the three-phase AC power supply to the compressor and the fan.

The invention relates to the technical field of plant illumination, and discloses a plant growth full-spectrum LED intelligent driving and dimming system which comprises a full-spectrum LED array module, a driving module, a control module, a sensing module and a feedback regulation and control module. The full-spectrum LED array module comprises five kinds of LED lamp beads and covers the ultraviolet A wave band and the spectral ranges of blue light, red light, far-red light and white light. And the driving module adopts a two-stage structure of a front-stage active PFC circuit and a rear-stage half-bridge LLC resonant converter. According to the plant growth full-spectrum LED intelligent driving and dimming system, a full-spectrum LED array module is optimized through an MATLAB exhaustion method to complete non-uniform layout, an illuminance sensor of a sensing module collects illumination data in a 100 ms period, a feedback regulation and control module calls a light uniformizing control algorithm to be combined with a Lambert formula and an improved Portrait equation to establish a precise mathematical model, and the precise mathematical model is used for driving the full-spectrum LED array module to conduct dimming on the full-spectrum LED array module. The double-closed-loop inner ring adjusts the PWM duty ratio of each LED branch in real time according to the PWM duty ratio, rapidly compensates illumination difference, and thoroughly solves the problem that the center is bright and the periphery is dark.

The utility model discloses a special high-performance four-quadrant frequency converter for the electromagnetic industry, which belongs to the technical field of power electronics, and comprises a main topology part and a control part, the main topology part comprises an input filtering part, a rectification filtering part and an inversion part, the input filtering part comprises a network side inductor L1, a filtering capacitor C1 and a machine side inductor L2, and the rectification filtering part comprises a three-phase half-bridge insulated gate bipolar transistor module, a first bus capacitor Cd1, a second bus capacitor Cd2, a first voltage-sharing resistor Rd1, a second voltage-sharing resistor Rd2 and a buffer loop. The inversion part comprises one or three paths of three-phase half-bridge insulated gate bipolar transistor modules, and the control part comprises a power supply board, a detection board, a rectification side main control board, an inversion side main control board, a rectification side driving board, an inversion side driving board and a driving board.

The invention discloses an SRM harmonic closed-loop torque ripple suppression method based on current square. The method comprises the following steps: (1) constructing an electromagnetic torque expression containing current square, and solving a current square harmonic model with optimal torque ripple; (2) obtaining a current square model with an optimal current square direct current bias value and an optimal torque ripple; (3) generating a fundamental wave amplitude reference value of the current square model with the optimal torque ripple, and obtaining a current square excitation model in an actual injection motor and an actual current square model of an output motor; (4) in order to realize closed-loop suppression of the torque ripple, the auxiliary channel executes a correction process; and (5) compensating an instantaneous torque peak appearing in a specific electrical angle range, completing harmonic closed-loop torque ripple suppression, and realizing an optimal torque ripple scheme. According to the invention, a double-layer compensation architecture based on current square harmonic injection and torque real-time feedback is constructed, so that the systematic suppression of the torque ripple of the switched reluctance motor is realized.