The buck-boost converter accepts the DC power typically 20V which generates the DC output based on the light sensor. The sensed output voltage and current makes the V-I characteristics of the PV panel emulator. The DIMM 100 control card is used to control the DC-DC boost converter stage. The boost stage is used to enhance the voltage from the panel and track the
Hence the boost converter can be redrawn as follows Fig. 4.2 Circuit diagram of continuous conduction mode During this state the inductor charges and the inductor current increases. The current through the inductor is given as Assume that prior to the opening of switch the inductor current is I’L, off. Since the input voltage is constant Assume the switch is open for ton seconds which is given by D*Ts where D is duty cycle and Ts is switching time period. The current through the inductor at the end of switch on state is given
Referring to the fig 3.1.1, the input to the system (usually square wave) is generated from the signal generator block. This signal is added to the block containing constant value one using the sum blocks. This makes the signal cycle about one position and this signal acts as a level input which is a desired value and the error signal i.e., the difference between the desired value and the actual value is given to the multiplexer block. The second input to the mux is the rate of outflow derived by differentiating the output level and passing it to the saturation block which limits the input signal to the low and higher saturation values. The multiplexer is used to overlap the input signals and pass them onto the next block.
The model of the inverter, of the input, Vpc, to output, IL, defined as Gi(s), is given by IL(s)/VPC(s)=((s.C+1/R0).n.Kinv)/(s2.L.C+S(L/R0)+1) (7) The closed-loop transfer function of the parallelism loop, ICLTF (s), is shown in Fig. 6 and is considered without simplification in the model of the inverter for the voltage loop. The transfer function defines the relation between the input IL and output V0. V0(s)/IL(s) =Gv(s)=1/(s.C+i/R0) (8) The model of the VSI, of the input, Vvc signal control, to the output, V0 voltage considering the inverter feeding a resistive load. The voltage controller selected was the Cv(s) =Kcv ((s+z1).
For system without compensation, the phase angle of current has been related to load giving active power in phase with load voltages. Since load assumed inductive it requires reactive power for proper operation and hence source must supply it which increases the current through source side via power line. If reactive power is supplied near load, the line current may be reduced which results in reduced power loss and improves the voltage regulation at load terminals. This can be done using current source, voltage source or with a capacitor. Current source device is used to compensate reactive components of load current which improves the voltage regulation of system and reactive current components from source is also reduced.
The Costas loop can be considered as a special version of the phase-locked loop (PLL). The PLL is designed to generate an electrical signal (voltage), the phase of which is automatically tuned to the phase of the input (reference) signal. Dynamic behavior of the PLL and the Costas loop has been described extensively in the literature [1–11], and a number of key parameters has been defined that describe its lock-in and lock-out characteristics. When the PLL is initially out of lock, two different types of acquisition processes can occur, either the so-called lock-in process or the so-called pull-in process. The first of those is a fast process, i.e.
In the former control, the inverter is operated in non shoot-through (ST) state with varying SPWM values between 0 ≤ M ≤ 1 and 0 ≤ M ≤ 2∕√3. The latter control utilized Simple boost, Maximum boost & Maximum constant boost control to get maximum voltage gain G which obtained by decreasing the Boost factor B and increases the Modulation index M as possible. Among all these methods, Maximum boost control will be efficient to give minimum voltage stress across the inverter but it introduce low frequency ripple content on the passive elements of the inverter. III. COMPARSION OF ZSI & QZSI IN VARIOUS RES Z source topology and its improved version Quasi Z source contributes more in Renewable energy systems like solar, wind and Fuel cell in the past two decade.
The first input to the valve subsystem is received from the fuzzy controller block and the second input consists of a constant block containing the value 0.5 which is the maximum inflow of the tank. The valve performs the control action by multiplying these two input signals. The manipulated variable (the inflow of the tank) enters the tank block and leaves the controlled level, the outflow and the overflow signal. The controlled level output is divided into two signals, one signal is fed to the comparison block and the other signal is fed back to the level input of mux. The signal that is fed back acts as a second input (rate) to the mux.
From the d.c. side capacitor, a three phase voltage is generated by the inverter. This is synchronized with the a.c supply. The link inductor links this voltage to the a.c supply side. This is the basic principle of operation of STATCOM. Fig 3.2 STATCOM is nothing but static shunt compensator which is connected in parallel at the point of common coupling and consists of static power devices like IGBT, MOSFET.