Position sensor-free control technology for four-phase doubly salient motor,Display control circuit and method and flat display device

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2 results about "Subtractor" patented technology

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In electronics, a subtractor can be designed using the same approach as that of an adder. The binary subtraction process is summarized below. As with an adder, in the general case of calculations on multi-bit numbers, three bits are involved in performing the subtraction for each bit of the difference: the minuend (Xᵢ), subtrahend (Yᵢ), and a borrow in from the previous (less significant) bit order position (Bᵢ). The outputs are the difference bit (Dᵢ) and borrow bit Bᵢ₊₁. The subtractor is best understood by considering that the subtrahend and both borrow bits have negative weights, whereas the X and D bits are positive. The operation performed by the subtractor is to rewrite Xᵢ-Yᵢ-Bᵢ (which can take the values -2, -1, 0, or 1) as the sum -2Bᵢ₊₁+Dᵢ.

Position sensor-free control technology for four-phase doubly salient motor

InactiveCN102904502ASolve the problem of high terminal voltage THD valueGuaranteed sineSingle motor speed/torque controlElectronic commutatorsTerminal voltageEngineering

The invention discloses a position sensor-free control method for a four-phase doubly salient motor. During electric running of the four-phase doubly salient motor, counter potential vectors differ from each other by 90 degrees in sequence in a d-q coordinate system. The control method comprises the following steps of: partitioning N (N is a natural number of more than 2) rotating speed ranges for designing wave filters of corresponding cut-off frequencies, only acquiring the terminal voltages of any two adjacent phases, entering a subtractor for removing direct current bias, judging the rotating speed of a motor according to a potential zero crossing point at a certain moment, deciding to enter a wave filter of a certain cut-off frequency through the rotating speed ranges, and acquiring the waveform of potential passing through the wave filter by using a DSP (Digital Signal Processor); establishing a phase shift angle comparison table of a wave filter which corresponds to a certain range specific to different rotating speeds in the range for performing DSP inquiry and corresponding accurate phase shift; and obtaining a practical phase change position through a zero crossing comparator, performing DSP computation, and outputting a driving signal to a switch tube by using an FPGA (Field Programmable Gate Array) to complete phase change. The four-phase doubly salient motor can work in a wide rotating speed range.

Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Display control circuit and method and flat display device

ActiveCN109147686AImprove display characteristicsNo other riskStatic indicating devicesCapacitanceComputer module

The invention relates to a display control circuit and method and a flat display device. The display control circuit includes a current source, a capacitor, a discharge circuit, a subtractor, and an initial reference voltage generating module. The current source is connected to a first end of the first capacitor to generate a charging voltage that changes with time, and a second end of the first capacitor is grounded. The discharge circuit is connected to a first end of the first capacitor to clear the charging voltage at the beginning of each frame of a display panel. A negative input end ofthe subtractor is connected to a first end of the first capacitor, a positive input end of the subtractor is connected to an output end of the initial reference voltage generating module, and an output end of the subtractor outputs an adjusted reference voltage. An output end of the initial reference voltage generating module outputs a fixed initial reference voltage. The adjusted reference voltage is used for generating a gamma voltage. According to the invention, for the gamma voltage of the display panel in the same frame, different gamma voltage adjustments at far and near ends are achieved, and the improvement of the display characteristics of the entire display panel is achieved.

Display control circuit and method and flat display device

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Owner:SHENZHEN CHINA STAR OPTOELECTRONICS SEMICON DISPLAY TECH CO LTD

2 results about "Subtractor" patented technology

Position sensor-free control technology for four-phase doubly salient motor

Display control circuit and method and flat display device

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