Circuits and methods for achieving high linearity, high efficiency power amplifiers, including digital predistortion (DPD) and pulse cancellation in switched-state RF power amplifier systems are described.

Linearization Circuits And Methods For Multilevel Power Amplifier Systems

A multi-level inverter having one or more banks, each bank containing a plurality of low voltage MOSFET transistors. A processor configured to switch the plurality of low voltage MOSFET transistors in each bank to switch at multiple times during each cycle.

Multi-level Inverter

An integrated power supply and modulator system includes integrated power supply and modulator system includes three subsystems: a switched-capacitor voltage balancer stage; a magnetic regulation stage; and at least one output switching stage In one embodiment, the integrated power supply and modulator system further includes startup circuitry, feedback/feedforward circuitry and control circuitry

Integrated power supply and modulator for radio frequency power amplifiers

In a time of increasing concerns about the immense energy consumption and poor environmental performance of contemporary processes in the chemical industry, there is great need to develop novel sustainable technologies that enhance energy efficiency. There is abundant chemical literature on process innovations (laboratory-scale) around the plasma reactor itself, which, naturally, is the essential part to be intensified to achieve a satisfactory process. In essence, a plasma process needs attention beyond reaction engineering towards the process integration side and also with strong electrical engineering focus. In this mini-review, we have detailed our future focus on the process and energy intensification of plasma-based N-fixation. Three focal points are mainly stressed throughout the review: (I) the integration of renewable energy; (II) the power supply system of plasma reactors and (III) process design of industrial plasma-assisted nitrogen fixation. These different enabling strategies will be set in a holistic and synergetic picture so as to improve process performance.

https://www.mdpi.com/2227-9717/2/4/694/pdf

Energy considerations for plasma-assisted N-fixation reactions

The invention belongs to the field of power converter control and relates to a model prediction control method of a voltage source type rectifier when a network voltage is unbalanced. The model prediction control method of the voltage source type rectifier when the network voltage is unbalanced comprises the steps of converting three-phase network voltage and a three-phase current into network voltage and a current which are under a two-phase static coordinate system through an abc / alpha beta coordinate, obtaining network positive sequence voltage and negative sequence voltage by carrying positive and negative sequence component separation of the network voltage under the two-phase static coordinate system, calculating reference values of active power, calculating current reference values of the rectifier under the two-phase static coordinate system, and carrying out model prediction current control and selecting an optimal on-off state. The model prediction control method of the voltage source type rectifier when the network voltage is unbalanced is capable of quickly and precisely tracing the current under the two-phase static coordinate and effectively eliminating fluctuation of direct current side voltage at the same time, power quality of the system is improved, a reliable network-connected operation of the rectifier when transient state network voltage is unbalance is achieved, and dynamics and stability of the whole system are improved.

Model prediction control method of voltage source type rectifier when network voltage is unbalanced

The invention relates to a control method of three-phase voltage type PWM rectifier under unbalance voltage of a power grid, relates to the technical field of power electrons. The method comprises the following steps: detecting three-phase power grid voltage value, and transforming to be under a two-phase static coordinate system; carrying out digital filtering on an Alpha-axis voltage component and a Beta-axis voltage component under the two-phase static coordinate system by a positive-negative sequence filter, and obtaining the Alpha-axis positive-negative sequence component and Beta-axis positive-negative sequence component; calculating and obtaining the Alpha-axis and Beta-axis current instruction according to the Alpha-axis and Beta-axis positive-negative sequence voltage component under the given active and reactive power and two-phase static coordinate system; detecting three-phase alternating current, transforming to be under the two-phase static coordinate system, adopting a predicting current control method, calculating and obtaining Alpha-axis input voltage instruction and Beta-axis input voltage instruction of the alternating side under the two-phase static coordinate system. SVPWM modulation is adopted to obtain driving pulse. The control method eliminates direct current voltage harmonic component of three-phase PWM rectifier under the unbalance voltage of the power grid and realizes the operation of controlled power coefficient.

Control method of three-phase voltage type PWM rectifier under unbalance voltage of power grid

The invention discloses a module combined multi-level converter, and belongs to the technical field of multi-level conversion. Three-phase alternating current wire connecting terminals of a first power unit (U1) are connected in series with n third power units (U3) (n is a positive integer, same below) in turn to form a three-phase upper bridge arm, three-phase alternating current wire connecting terminals of a second power unit (U2) are connected in series with n fourth power units (U4) in turn to form a three-phase lower bridge arm, the three-phase upper bridge arm is connected with the three-phase lower bridge arm through two electric reactors, and a connecting point between the two electric reactors is a three-phase alternating current output end. A direct current wire connecting terminal of the first power unit (U1) is connected with an anode (101) of a direct current bus, and a direct current wire connecting terminal of the second power unit (U2) is connected with a cathode (102) of the direct current bus. By increasing or reducing the number n of the power units of the upper bridge arm and the lower bridge arm, the level number of the converter can be changed. The module combined multi-level converter preserves the advantages of the conventional multi-level converter, overcomes the defects of the conventional multi-level converter, and can be applied to an energy conversion system of medium-high voltage high-power occasions.

Module combined multi-level converter

The invention discloses a weak magnetic control method for a permanent magnet synchronous motor. The method comprises the following steps that: direct axis current instructions are obtained through a motor rotating speed regulator; and instruction values of motor alternating axis voltage are obtained by calculation through the direct axis voltage instruction value output by a motor direct axis current regulator and the maximum voltage value output by an inverter, and the motor voltage is guaranteed to reach the maximum value at the weak magnetic interval. The method provided by the invention can be used for solving the problem of nonideal system control effect caused by alternating and direct axis current coupling in weak magnetic control, and in addition, the voltage utilization rate can be improved.

Weak magnetic control method for permanent magnet synchronous motor

The invention belongs to power supply, in particular to a method for suppressing line-side harmonics of a magnetic-levitation train tractive power supply system capable of feeding back braking energy.The method comprises the following steps: a controller transforms an input current and an input voltage of an alternating current-direct current (AC-DC) transformation device into a current and a voltage in a rotating coordinate system by dq coordinate transformation; after the current and the voltage pass by a low-pass filter, the current is projected in a voltage direction, the projection is compared with an adjusted difference value between a positive DC bus and a negative DC bus by a proportional integral controller to obtain projections of a current active component on a q-axis and a d-axis; the projections on the q-axis and the d-axis are inversely transformed from a phase-locked ring at an angular frequency extracted from the input voltage to obtain a fundamental wave current active component; the difference of the fundamental wave current active component and the input current is a compensating current component which is compared with a practically measured AC of a three-phasefour-quadrant converter to obtain an error signal; and the turn-on time and the duty ratio of each power switching tube of the three-phase four-quadrant converter are calculated by using the error signal and a deadbeat predictor current control method, thereby sending out a PWM control signal of each power switching tube.

Method for suppressing line-side harmonics of magnetic-levitation train tractive power supply system capable of feeding back braking energy

The invention provides an H6 one-phase non-isolated photovoltaic grid-connected inverter, comprising six switch tubes, a filtration module and a modulation circuit module, wherein a source of the first switch tube is connected with the drain of the second switch tube and one end of an alternating current side; the source of the second switch tube is connected with the source of the fourth switch tube and the drain of the six switch tube; the drain of the fourth switch tube is connected with the source of the third switch tube and the other side of the alternating current side; the drain of the third switch tube is connected with the drain of the first switch tube and the source of the fifth switch tube; the drain of the fifth switch tube is connected with the positive electrode end of a direct current side; the source of the six switch tube is connected with the negative electrode end of the direct current side. By using the inverter, the common mode current harm is effectively eliminated, and the modulation method has a three-level modulation effect; in addition, only two switch tubes work at high frequency, the other four switch tubes work at a half of the frequency, the total harmonic distortion of grid-connected current is reduced, and the efficiency is improved. The invention also provides a modulation method of the H6 one-phase non-isolated photovoltaic grid-connected inverter.

Hu Sun

Papers

Control method of three-phase voltage type PWM rectifier under unbalance voltage of power grid

Module combined multi-level converter

Weak magnetic control method for permanent magnet synchronous motor

Method for suppressing line-side harmonics of magnetic-levitation train tractive power supply system capable of feeding back braking energy

H6 one-phase non-isolated photovoltaic grid-connected inverter and modulation method thereof