| This text must through what is exchanged the exposition of the important function of the voltage of steady voltage and cut accusing of type state of development and current situation of exchanging the voltage of steady voltage and proposed researching and developing both at home and abroad in cutting the accusing of type Wanting. On the basis of cutting principle of accusing of in elaboration , have proposed the control scheme of this system. First of all, according to establishing the voltage and relation of inputting the voltage , to confirm the polarity of compensating voltage transformer . Voltage of introduction that is calculated out then according to every half a cycle , outputting the voltage , outputting the virtual value of the electric current, calculate out PWM pulse width that should be provided this time through PID. In order to achieve the goal of regulating dynamically , can realize the steady output of the voltage . This system includes two control rings : The External Loop controls the ring for the voltage, the Inner Loop is a ring of the electric current. The External Loop carries on figures and strains waves, get the virtual value of outputting the voltage; Give with output virtual value definitely Vs, compares , its error signal and then regulates the amplitude of the setting value of controlling the sinusoidal wave signal of the standard via PI controller . The power is controlled through the External Loop of virtual value, can make sure that there is not difference to output the voltage virtual value stable state in theory , it's time to control the purpose of the ring is for guarantee to maintains the stable state which outputs the virtual value of the voltage and does not change after load changes , the system is interfered, namely the precision of stable state of voltage of output of the security system. The Inner Loop should surround and control the instantaneous value which output the electric current in order to output the instantaneous value feedback control ring of electric current, is it output voltage follow give definitely sinusoidal wave , keep good sine nature that output to make, having enough abundant degree of stability for the security system, controller that should be surrounded adopt more controllers of proportion (P ), or the controller of proportion differential (PD ). The main function that should be surrounded is to overcome and interfere it to outputting the influence of the voltage wave form for guarantee to output the sine of the voltage, improve dynamic performance of the control system and stable state performance .Under controlling the guidance of the scheme , to design the hardware circuit. The hardware circuit is made up of several following parts mainly: Compensate voltage transformer , relay and urge compensation polarity some change that return circuit form , IGBT urge some , top management board , IGBT time sequence part that CPLD form. Compensating the voltage transformer should realize regarding voltage establishing value as the central point , is shouldering two directions and each compensating 40V. The relay had better adopt the solid state relay , the response time is short. IGBT selects GT30J301 of TOSHIBA for use. This IGBT has connected the diode in parallel instead in collector and emitter.The top management chip that this system adopts is dsPIC30F4013. It is a digital signal controller of 16 persons of flashing memory (DSC ), adopts high performance to revise RISC CPU, the speed of performance is up to 20 and 30MIPS, have it from the programming function through flashing , can work in industry and expand the temperature range。Regard Rhapsody based on UML language as the frame and put up and control the procedure entirely. Rhapsody can pass IDF to use in having limited goal system of operating system resource (Interrupt Driven Framework stops driving the frame ) run . There is IDF, the code that the model produces no longer needs participation of the embedded operating system. In addition, the code produced is optimized again in many aspects, what the code of the light heavyweight can be operated is small fast. IDF of Rhapsody 7.0 applies some Rhapsody models to some harsh environments possibly, such as 8, in the environment of expecting much in 16 processors or the little performance of memory space. Regard Rhapdosy based on UML language as frame, make procedure making module, easy to maintain , debug , update of product. Have optimized and tested the whole system.In the whole system, more difficult part is the sureness of PID coefficient. The task that the parameter of PID controller is exactly made is Kp which confirms digital PID, Ki, Kd, to the simple system , can confirm these parameters by calculating in theory . But a little more complicated system, it is difficult to adopt the theory to calculate. So nearly all exactly makes the parameter by way of project. This system comes by the way of combining with experiment in emulation to confirm this coefficient. |
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