Papers by Keyword: Digital Control

Abstract: Zvzcs-pwm inverter combines the advantages of ZVS-PWM inverter and ZCS-PWM inverter, it can solve the problems of switching loses and extra circulation. Furthermore, it is provided with less duty cycle loss, small parasitic oscillation of the secondary side and large load rage conducted by soft-switching. A conjoint system based on MCU and DSP can make full use of the advanced ability of the event management, data processing and computing speed, which improves accuracy and real-time digital control of arc welding power. This paper introduces design of main circuit and control circuit of arc welding power and the working process of the zvzcs-pwm inverter. The simulation with matlab demonstrates the feasibility of the design.

Abstract: Based on the need to develop and test the products, a single phase DSP­based programmable AC power supply is designed. The power supply is capable of providing a stable AC voltage with adjustable amplitude and frequency over a wide range. Moreover, it can generate various high quality and low frequency arbitrary waveforms. Because of the advantages above, it will have great value in practice and a promising future in testing field. The main circuit of the power supply is to use rectifier and filter to make 220V AC voltage become steady DC voltage firstly. Then the inverter and the LC LPF are employed to produce the AC voltage which is required in the test system. The key part of the inverter is phase shift full bridge.

Abstract: Traditional analog-controlled DC/DC converter can only employed easy control method and always has complicated hardware structure. Its extremely unfavorable in improving efficiency and reducing the cost of hardware. In this paper, a new full digital control method has been proposed. This method employed an advanced main circuit topology combining with an ARM MCU, it can reduce power supplys volume and cost, improve its efficiency effectively. The Topology of main circuit is reasonable, the design of parameters was right. All the results were consistent well with theory analysis. The power supply can realize leading legs ZVS and lagging legs ZCS in a big load range. The whole system has concise hardware structure, reliable control method and good man-machine interface, so it has high practical value.

Abstract: In order to provide stable and adjustable current source for portable systems, this paper designs a digitally controlled constant current source. According to the input of independent key, the output of the microcontroller digital volume controls digital-to-analog converter by Voltage-Current conversion module to get the constant current output. The output module consists of the operational amplifier and the power transistor TIP122, which is used for voltage-current conversion. At the same time, the value of output current is obtained by sampling resistor to convert the real-time acquisition and monitor the output of constant current source. The experimental results show that the system output ranges from 0 mA to 240 mA. The value of constant current can be controlled by stepper key, and the measurement error ratio can meet the requirement of design.

Abstract: A new three-phase power-factor-correction (PFC) scheme is discussed using two single phase power factor correction circuit parallel connected. Two phase orthonormal voltage is produced by means of a auto transformer from a three phase input,fluctuation of neutral point by three single phase power-factor-correction circuit parallel connected is canceled,coupling interference is reduced among three phases,digitally controlled Power Factor Correction Boost Converters is adapted,input current wave sine with unity power factor suppress the secondary harmonic of input AC side is realized,voltage and low current stresses across each switch are reduced. Simulation and experimental results prove that it can achieve high power factor,low current,good capability of anti-interference and high reliability.

Abstract: Mathematical model of tension servo system drived by two induction motor is analyzed in this paper. Then, structure optimized of first-order active disturbance rejection control (ADRC) of tension servo system is designed. Double channels compensation of extended state observer is used to estimate and compensate the total disturbance of system, and approximate linear and determined treatment is done to the tension control system. S7-300 PLC is used as lower computer controller, while WinCC is used as upper computer monitor software, realizing all-digital control of the system. The experiments is carried on based on S7-300 PLC experimental platform and the results prove that the decoupling control of speed and tension is realized, and the control system has higher dynamic, static status and robustness performances.

Abstract: Abstract: In the current domestic control system of submerged arc welding machine, most walking DC motor speed control uses the method of analog control pulse width modulation (PWM), which has a complex circuit, high failure rate and is inconvenient to use. For this phenomenon, DSP (TMS320F2812) disc is used to build a digital control system, and replace the traditional analog controller, allowing the weld control system more simple and practical. The main content of this paper is the hardware circuit design and software algorithms programming of digital control DC speed control system. Tested by experiment, this digital control system can replace the weld analog control system, enabling the motor to have good control performance at low speed thereby enhancing the welding effect of submerged arc welding machine.

Abstract: This paper introduces a power factor correction (PFC) main circuit adopting novel full bridge topology, in which the clamped capacitor limits voltage stress on the switch tube, reduces output voltage ripple, and improves the response velocity; TMS320F2812 series DSP, produced by TI company, is used as the main control device in this system, and the DSP fixes the switch frequency at 20kps. It uses alternate sampling method to avoid the switching noise taken into the system. And then, both the validity of the theoretical analysis and the effectiveness of the control strategy are verified by the prototype test.

Abstract: The research interest of this paper is to explore practical ways of incorporating advantages of digital control in Switching Mode Power Supply (SMPS). The two most important issues are the design and implementation of Digital Pulse-Width Modulation (DPWM) and high-performance digital control algorithms for digital controlled SMPS. A Hybrid DPWM method based on digital clock management (DCM) and digital dithering is adopted to generate high-frequency high-resolution PWM. A digital V2 control algorithm is implemented to improve the system performance. The buck converter is studied to analyze the digital V2 control application in SMPS. The simulation and experimental results are presented.

Abstract: A new full digital control method has been proposed. This method employed an advanced main circuit topology combining with an ARM MCU. Using the state space averaging method and following the method deriving the small-signal model of Buck converter, the small-signal characteristics model of DC/DC converter can be derived. Using no steady error quadratic optimal control method, the problem of PID parameters is transformed into solving optimal feedback coefficient matrix, the digital controller of full-bridge DC/DC converter can adjust the parameters online. The power supply can realize leading leg’s ZVS and lagging leg’s ZCS in a big load range. The whole system has concise hardware structure, reliable control method and good man-machine interface, so it has high practical value.