154results about How to "Suppress ripple" patented technology

The present invention aims to provide a synchronous motor drive system that is capable of suppressing ripples in current while reducing switching loss. The system includes three-phase inverters 201-203, a control circuit 400 for controlling the operations of the three-phase inverters and a synchronous motor 300 including a plurality of three-phase coils. To control the operations of the three-phase inverters, the control circuit 400 causes the three-phase inverters 201 and 203 and the three-phase inverter 202 to use different carrier frequencies to generate three-phase AC power, and each of the three-phase inverters supplies a different one of the three-phase coils with three-phase AC power.

The invention discloses a modularized multi-machine parallel-connection large-power APF (active power filter) control system and a realization method. By coordinating an upper layer controller and a lower layer controller, an effect for reasonably allocating the compensative capacity and improving the compensation precision can be realized; the upper layer controller is used for carrying out the coordination and switching control on each power module, for example, the upper layer controller is used for operating and monitoring the quantity of the power modules to be put into use according to a load requirement, numbering the power modules according to a rule and eliminating the switching subharmonic by utilizing the carrier phase shifting; the lower layer controller is used for receiving a compensation order of the upper layer controller and a synchronous signal of a previous sequence number controller and feeding back state information of the power module to the upper layer controller. By adopting the modularized multi-machine parallel-connection large-power APF control system, the compensation capacity of the power module and the computation of an upper layer and a lower layer of the control system are reasonably allocated, the entire system can be enabled to run stably and orderly, the stopping of the entire system caused by the malfunction of one power module can be avoided, and the feasibility and practical value are good.

In an inverter apparatus, an output voltage of an active filter circuit that steps up and smoothes a DC voltage is converted into an AC voltage by an inverter circuit. The active filter circuit includes a capacitor and a rectifier device connected between an input node and an output node. An inductor, one end of which is connected to the input node and the other end of which is connected the output node through the rectifier device, and a switch device connected between the other end and a low-potential-side line, and a first control circuit for the switch device are provided. The inductor stores energy while the switch device is on and releases the energy while the switch device is off. The rectifier device conducts such that the stored energy of the inductor is released.

The objective of this invention is to reduce the current flowing through the inductance element in a step-up/step-down DC-DC converter and to control the ripple in the output voltage. In the DC-DC converter, four states, that is, the first state [1] of (M1, M2)=(off, on) and (M3, M4)=(on, off), the second state [2] of (M1, M2)=(on, off) and (M3, M4)=(off, on), the third state [3] of (M1, M2)=(on, off) and (M3, M4)=(on, off), and the fourth state [4] of (M1, M2)=(off, on) and (M3, M4)=(off, on) are repeated in a prescribed order, preferably in the order . . . [1]→[4]→[2]→[3]→[1] . . . or . . . [1]→[3]→[2]→[4]→[1] . . . .

The invention discloses an optimization control method for a Boost PFC comprising an active energy storage unit, and belongs to the field of AC-DC power conversion. The invention aims at a problem of reference distortion, caused by the condition that an output voltage of a rectifier bridge is taken as a sine reference, in a conventional Boost PFC mean current control method. The method comprises the steps: converting an input sine voltage into a square signal through a square wave conditioning circuit, enabling a digital controller to capture the rising and falling edges of the square signal, and generating a pure sine signal as a sine reference through an anti-error capturing phase-locking algorithm, so as to improve the reference distortion; deducing an input feedforward and load feedforward algorithm on the basis that a sine reference control method is generated, so as to improve the capability of an output voltage in resisting input and load disturbance and increase the tangential velocity of a light load tangential algorithm. The method achieves the deduction of an input current of the active energy storage unit as the reference through the generated sine signal and the output current, and saves a band-pass filter circuit which samples the input current reference of the active energy storage unit. Moreover, the method improves the power density and efficiency of a converter.

The invention discloses a high-gain and wide-duty cycle control Boost converter and belongs to the technical field of converters. The high-gain and wide-duty cycle control Boost converter disclosed bythe invention is characterized in that a clamping absorption unit 1 is composed of a clamping diode D1 and a clamping capacitor C1; a clamping absorption unit 2 is composed of a clamping diode D2 anda clamping capacitor C2; a pressure doubling unit 1 is composed of a capacitor C3, a diode D3 and a secondary winding L1b of a coupling inductor T1; a pressure doubling unit 2 is composed of a capacitor C4, a diode D6 and a secondary winding L2b of a coupling inductor T2. The high-gain and wide-duty cycle control Boost converter disclosed by the invention has the benefits that on the basis of thebasic Boost converter, the coupling inductor T1, the pressure doubling unit 1, the coupling inductor T2 and the pressure doubling unit 2 are respectively added to obtain two different forms of Boostconverters; the input sides of the two different forms of Boost converters are connected in parallel, and the output sides are connected in a manner of series connection of the capacitors, so that theconverter has higher boosting capacity; the voltage stresses of a switching tube and the diodes are reduced, and the voltage gain can be adjusted within a duty cycle range that d is less than o but more than 1.

The image forming apparatus of the present invention includes an image forming member that jets liquid droplets onto a recording medium and forms an image on a front face of the recording medium, a tension imparting member that induces tension of 100N/m to 1000N/m in the recording medium image-formed on the recording medium front face by the image forming member, and a drying member that dries the image formed on the front face of the recording medium when tension induced in the recording medium by the tension imparting member to a residual moisture level of 3 g/m² or less in the recording medium.

The present invention provides method of generating threshold matrix and recording medium storing data of threshold matrix. In a matrix area (720), a plurality of highlight-side dot centers (731) and a plurality of shadow-side dot centers (741) are regularly arranged and a plurality of reference points (751) are set while being distributed almost uniformly. Each of the dot centers (731, 741) is rotated about a nearest reference point (751). Threshold values of the matrix area (720) are determined so that halftone dot areas should be changed around a plurality of highlight-side dot centers (731) after being rotated in accordance with the variation in gray level on the highlight side and a halftone dot area (i.e., joined dot areas) should be changed around a plurality of shadow-side dot centers after being rotated in accordance with the variation in gray level on the shadow side. In a halftone dot image generated by using the matrix area which is thus generated, it is possible to suppress moire and graininess.

The invention discloses a ripple wave suppressor circuit of a program-controlled direct-current power supply. According to the ripple wave suppressor circuit of the program-controlled direct-current power supply, an active low-pass filter and a passive filter are connected between a positive output line of the direct-current power supply and a negative output line of the direct-current power supply after a capacitor C3 is connected between the positive output line of the direct-current power supply and the negative output line of the direct-current power supply, the active low-pass filter comprises an N-channel high-power MOSFET V1, a front-stage operational amplifier N1:1 with a dynamic compensation function and a rear-stage operational amplifier N1:2 with a dynamic compensation function, and the passive filter comprises an inductor L1 and a capacitor C1. According to the ripple wave suppressor circuit of the program-controlled direct-current power supply, high-frequency and low-frequency ripple wave noise output by the power supply can be lowered, the dynamic response performance can be improved, and the output precision and the stability are improved. The front-stage and rear-stage synchronous tracking control is adopted, accurate adjustment enabling the voltage difference to be low can be achieved, and the conversion efficiency of the power supply is effectively improved. As a result, the ripple wave suppressor circuit of the program-controlled direct-current power supply has high application value in the aspect of design of high-precision program-controlled power supplies.

This conductive film has a difference of over 3 cycles/mm between a peak spatial frequency for a plurality of spectral peaks in a two dimensional Fourier spectrum for transmittance image data for a wiring pattern and a peak spatial frequency for spectral peaks up to the second term in a two dimensional Fourier spectrum for transmittance image data for a microprism array pattern for a prism sheet on the display unit side of a backlight unit, for a first moire obtained by interference between a wiring pattern for a conductive section and the microprism array pattern. As a result, this conductive film is capable of suppressing the occurrence of moire and can greatly improve visibility, even when arranged upon a display unit having a backlight unit using a prism sheet.

The application discloses a single-phase inverter and a DC bus ripple suppression method thereof. The method is applied to the single-phase inverter externally connected with hybrid capacitors on a DC bus. The hybrid capacitors include a compensation capacitor, a DC bus capacitor, and a bidirectional conversion circuit of which one end is connected in parallel with the compensation capacitor and the other end is connected in parallel with the DC bus capacitor. The method comprises the steps that an instruction value of the output voltage instantaneous value of the compensation capacitor is generated; and pulse width modulation is performed on the bidirectional conversion circuit so that the compensation capacitor is enabled to output according to the instruction value. DC bus ripple can be suppressed without increasing the capacitance value of the DC bus capacitor.

Provided is a motor controller for controlling a motor system including a power converter, a smoothing capacitor and a three-phase AC motor. The motor controller includes a generation unit configured to generate a modulation signal by adding a third harmonic signal to a phase voltage command signal, and a control unit configured to control an operation of the power converter using the modulation signal. The third harmonic signal includes a first signal component that causes an absolute value of a signal level of the modulation signal to be greater than an absolute value of a signal level of the phase voltage command signal at a timing in which an absolute value of a signal level of a phase current becomes minimum in each phase

This invention provides a switching power supply control circuit based on the parallel operation scheme that suppresses ripples in the output voltage. The control circuit comprises switching circuit blocks 10 and 20 connected in parallel, output reactors 31 and 32 connected in parallel corresponding to the switching circuit blocks 10 and 20, and a control circuit 40 that controls the operation of the switching circuit blocks 10 and 20. The control circuit 40 comprises: means of calculating the difference between the reactor currents I_L1 and I_L2 flowing through the output reactors 31 and 32 and the average value of the reactor currents, means of generating control voltages V_o1 and V_o2 corresponding to the switching circuit blocks 10 and 20 based on the calculated differences and the output voltage V_op comparators 48 and 49 that compare the control voltages V_o1 and V_o2 against the reference voltage V_ref and latch circuits 51 and 52 that latch the outputs of the comparators 48 and 49 in response to the clock signal CLK.

The present disclosure provides a mirror device with illumination comprising a transparent conductive substrate, an isolation layer, a mirror layer and a light emitting diode (LED) layer. The isolation layer, formed on a surface of the transparent conductive substrate, divides the surface of the transparent conductive substrate into at least one first region and at least one second region. The mirror layer formed on the transparent conductive substrate within the at least one first region, while the LED layer is formed on the transparent conductive substrate within the at least one second region, wherein the mirror layer and the LED layer are electrically isolated from each other. In another embodiment, the present disclosure further provides a mirror box having the mirror device with illumination disposed therein so that the mirror device can be easily carried and kept in the pocket, or purse of user.

A recording apparatus is provided which includes: a recording unit that performs a recording operation on a target by causing liquid to adhere onto the target; a drying unit that performs a drying operation on the target on which the liquid is adhered by the recording operation of the recording unit in a state where a restricting force is not substantially applied thereto; and a restricting unit that performs a restricting operation on the target which has been subjected to the drying operation by the drying unit while supporting the target on a supporting face of a support member capable of supporting a surface of the target having the liquid adhered thereon in a uniform planar state, the restricting operation applying a restricting force to the target, the restricting force being directed toward the supporting face.

The invention relates to a PSCAD modeling and simulation method for a grid-connected inverter during an unsymmetrical failure of a power grid and belongs to the technical field of PSCAD modeling and simulation methods. The technical problem to be solved is providing a PSCAD modeling and simulation method for a grid-connected inverter under a positive-negative dual-sequence independent control strategy. The technical scheme comprises following steps: first, the positive-negative sequence voltage and current of the three-phase voltage and current of the AC side of the grid-connected inverter are separated; the three-phase positive and negative voltage and current are converted to a [alpha][beta] axis to obtain reference values of positive-negative sequence current of a dq axis; then the PI parameter of current inner loop and voltage outer loop is calculated. The method is suitable for electrical power systems.

The invention discloses electron beam control system and method for an electronic gun. An additional self-current-stabilizing device comprises passive elements such as a resistor or inductor. The self-current-stabilizing device (6) is serially connected to an electron beam circuit. One end of the self-current-stabilizing device is connected to a positive output electrode of a gate-bias power supply unit (3). The other end of the self-current-stabilizing device is connected to a positive output electrode of a bombardment power supply of an indirect-heating electron gun or an optional output electrode of a filament power supply of the indirect-heating electron gun. Constant voltage Ue relative to an electron beam and generated by the indirect-heating electron gun is directly superposed to gate-bias voltage to form local non-delay negative feedback, and current stabilization is achieved.