Integration of EV Converter/Inverter stations and PV farm on Power Quality of Grids using PSCAD With the increasing penetration of renewable energy. Inverter-Based Resources (IBRs) are gradually replacing synchronous generators in power grids. Present-day IBR control may be insufficient to ensure grid stability in a future inverter dominated power grids. One of the main causes of instability is poor power quality. In this assignment you will be investigating the power quality of a typical IBR grid as shown in the circuit of the figure below. The figure consists of a single phase 240 Vrms, 50 Hz source and: • Three resistive loads. Each load has a resistance of 48 0. • Three EV charging converters/Inverters through a 24 resistor. • A solar farm that is composed of 15 PV panels. Each panel has a rating of 24 V and current of 15 A. Panels are connected in series and parallel to provide an output voltage and current of 240 Vrms and 45 A respectively. 240 Vrms 50 Hz V, 1,1 Transmission Line 1 TL1 -0.05 Transmission Line 2 Mini Solar Farm TL2 = 0.05 P Converter N 24 460 52 EV Converter/Inverter FL 480 Load/nDemonstration of the above concept will be achieved with the following steps: I. Construct the skeleton of the given circuit in PSCAD. Design appropriate Inverters/Converters for this circuit. Calculate all the required values for each circuit component etc. II. III. IV. Measure voltage and current at the generator side and then investigate the quality of measured V, I and frequency for the following scenarios: a) The circuit operating under fully normal conditions (without the EV charging/discharging stations and Solar farm) b) The circuit operating in semi normal condition (some of the EV charging stations and the solar farm are switched in) c) The circuit operating under no normal conditions (the EV charging stations and/or solar farm are switched in and out). Marking Scheme Introduction and Literature Review 10 Marks Design of Inverters and converters 10 Marks Creating various scenarios with the given switches in the above circuit. 10 Marks Construction of the above circuit in PSCAD 20 Marks Results and Analysis: Demonstration of scenarios with the constructed circuit in PSCAD Conclusion and report presentation 10 Marks References Bonus for employment of PV module and EV Module Published date: 10th October 2023 extension pscx 10 Marks 10 Marks 20 Marks (Please note, you will need to submit your constructed PSCAD file with ()

Write the general equation governing the photo generation phenomenon in a PN junction diode. In the equation you should have the current-term due to the voltage biasing and the photo generated current term due to an incident light. Mark the terms in your provided equation. (1) Draw the I-V current relation (I versus V plot) for changing gop (rate of optical generation). (2) Which quadrant of this I-V relation is utilized for solar-cell applications. (mark in your I-Vcurve)? (3) Which quadrant of the I-V relation is utilized for photo-detector application (mark in your I-Vcurve)? Now consider the photogeneration current term. What will be the effect on photo generated current, if the P and N sides are highly doped in comparison to light doped. (hint: how depletion region width changes? How does depletion width change the current?)

(a) The DC chopper in Fig. Q5(a) has a resistive load, R=30 £2, and input voltage V₁=230 V.The on-state voltage drop of the switch is 1.5V and the switching frequency is 15kHz. Ifthe converter duty cycle is 65%, calculate: (i)The mean load voltage. (ii)The RMS load voltage. (iii) The ripple factor of the output voltage (iv) The converter efficiency (b) In power electronic equipment, most of the waveforms are non-sinusoidal. Discuss: (i) The significance of the presence of voltage/current harmonics caused by AC/DC converters. (ii) How the impact of those harmonics can be mitigated in power electronic circuits. (c) With the aid of a well labelled diagram, explain the application of power electronics in solar photovoltaic energy systems.[4]

WINCH DRIVE USING SINGLE-PHASE CONTROLLED RECTIFIER A Separately-Excited DC Motor is driving a Winch Drum through a 1:10 speed reduction gearing system. The diameter of cable drum is 40 cm. The motor is a 367 Frame Size whose parameters are: 230 V, 30 hp, 1150 RPM, 108 A, 0.0963 armature resistance. The motor armature inductance is assumed large enough such that the armature current is assumed ripple-free. The motor is driven from a 240 V, 50 Hz sinusoidal source through a single-phase controlled rectifier. The motor field current is assumed constant at rated value. (1) Is the motor capable of raising the load at rated loading conditions? If not, calculate the maximum linear velocity of the load while raising up. Then evaluate the THDF of the supply current and the input power factor of the system. Assume constant rotational loss. (2) If the motor is to raise the load at rated conditions (i.e., torque and speed), what would you suggest? In this case calculate the possible linear velocity of the system while raising up. (3) If the motor is to lower the load at the same raising speed without overloading, calculate the firing angle required for this purpose, and evaluate the THDF of the supply current and the input power factor of the system. (4) If the motor is to hold the load at standstill, what is the value of the load current to do so? Can you comment on such a situation?

EXERCISE 1: Closed-Loop Controller Design and Simulation of H-bridge DC/AC Inverter Use Matlab/Simulink. You can use SimPower or Simscape libraries to simulate components needed in power electronics. Key elements that you need to simulate an H-bridge DC/AC Converter as shown in the figure above: • Four Mosfets • One Inductor One Capacitor One Resistor • DC Voltage Supply PWM Generator Other elements needed to run the simulation (not essential in the converter operation) L1 000 DC Supply Q1 Q2 TAT The preliminary design parameters are: Q3 Q4 -Vm=d(t)V de- -lout" C1 R1

3. A buck-boost converter with an input voltage of 40V is used to regulate the load voltage in the range of 10 to 80V. The on-time of the transistor is always fixed at 0.1ms and the switching frequency is adjusted to regulate the load voltage. Compute the range of switching frequency.

2. A boost converter is used to step up 25V into 40V. The switching frequency of its transistor is 1kHz, and the load resistor is 10092. Compute a) The current ripple when the inductor is 30mH. b) The average current of the load c) The power delivered by the source

Consider the DC Motor control set-up in Fig. 1. VDC V (D) Fig. 1. H-bridge drive system for DC motor DC Motor 1) Considering bipolar switching, compute the average value of the voltage across the terminals of the DC motor as a function of the duty cycle V, (D). Justify your answer using a diagram of the circuit and the step-by-step averaging procedure.

EXERCISE 2: Closed-Loop Controller Design and Simulation of H-bridge DC/AC Inverter with PV Objectives: - Getting familiar how a PV source operates when interfaced with an H-bridge PV Inverter Author: Babak Parkhideh, PhD You need to take the "PV Array" block from the Simulink Library. Choose the SolarWorld Sunmodule Plus SW 250 mono Black from the Module data drop-down list. We use only one panel throughout the lab. First, consider the nominal operating points defined in the PV panel datasheet (mentioned in the Simulink interface too). Use the nominal parameters you have chosen in Exercise 1. You need to consider a DC link capacitor in parallel to the PV panel. Make sure the DC link voltage ripple in less than 2V at the nominal operating point. Construct the closed-loop feedback simulation model of the inverter interfacing with the PV array. If you have constructed the model in the previous labs, update the model. You can use the architecture shown below. Use the PID block in Simulink. Choose a proper Time Domain you have worked with, Continuous vs. Discrete. + Note that the modulation index must be sinusoidal to generate a 60Hz output. Make sure the compensator output is multiplied by Sin(2pi60t). Or, use the dq transformation or similar to extract the rms or mean value of the current. Multiply the current controller output by Sin(2pi60t). DC Link Voltage- Reference (PV Voltage) PID lac-ret Revised 10/04/2021 Duty cycle Page 4 of 6 Current Controller PWM PV Inverter DC link Voltage, Voc

a) Choose the BEST answer only for each of the following questions: (ii) In a three phase uncontrolled full wave rectifier, each diode conducts for: (iii) The switching control action in Fig. Q4(a-iii) is known as: (iv) The ratio between the height of the reference wave and the carrier wave in inverter-control is called: (v) For the three phase inverter circuit shown in Fig. Q4(a-v1), the state given in Fig.Q4(a-v2) results in which combination of line voltages? (vi) The AC voltage of a square wave inverter is likely to have which of the following harmonic contents? (vii) The extent of harmonic pollution in a current or voltage waveform can be determined by: A three-phase fully controlled bridge rectifier is delivering a constant DC current of 50A to load from a 415V, 50Hz three phase source with a source inductance of 4.8mH per phase(and negligible source resistance). Neglecting the Thyristor forward voltage drop, for a firing angle of 45° determine: (i)The mean output voltage of the circuit The overlap angle The generalised mean output voltage of a p-pulse converter is given by the expression: V_{\text {mean }}=\left(\frac{p V_{\max }}{\pi} \sin \frac{\pi}{p}\right) \cos \alpha-\frac{p X}{2 \pi} I_{L} The generalized expression of mean voltage with overlap angle y is expressed as follows: V_{\text {mean }}=\left[\frac{p V_{\max }}{\pi} \sin \left(\frac{\pi}{p}\right)\right]\{\cos \alpha+\cos (\alpha+\gamma)\} (c) With the aid of appropriate sketches, discuss how a pulse width modulated control signal with variable duty cycle can be generated to control a dc/dc converter.[6]