Problem 14 P 34, Problem 15 P 34, Problem 176 P 945

Problem 14 P 34 Problem 15 P 34 Problem 176 P 945 Pro

Problem 14 P 34 Problem 15 P 34 Problem 176 P 945 Pro · Problem 1.4 (p. 34) · Problem 1.5 (p. 34) · Problem 17.6 (p. 945) · Problem 17.8 (p. 945) · Problem 17.14 (p. 946) Submission Requirements: 1.4 The peak value of the current waveform through a power device as shown in Figure 1.10d is IP = 100A. If the duty cycle k = 40% and the period T = 1 ms, calculate the rms current IRMS and average current IAVG through the device. 1.5 The current waveform through a power device is shown in Figure 1.10e. If Ia = 80 A, Ib = 100 A, the duty cycle k = 40%, and the period T = 1 ms, calculate the rms current IRMS and average current IAVG through the device. 17.6 An RC snubber circuit, as shown in Figure 17.16c, has C = 1.5 μF, R = 3.5 Ω, and the input voltage is Vs = 220 V. The circuit inductance is L = 20 μH. Determine (a) the peak forward voltage Vp, (b) the initial dv/dt, and (c) the maximum dv/dt. 17.8 An RC snubber circuit, as shown in Figure 17.16c, has circuit inductance of L = 60 μH. The input voltage Vs = 220 V. If it is necessary to limit the peak voltage to 1.5 times the input voltage, and the damping factor, α = 9500, determine (a) the snubber capacitance C, and (b) the snubber resistance R. Assume frequency f = 8 kHz. ET3380: Module 1 Basic Principles of Electronic Power Conversion Lab 1.1 Handout 1 Activity 1. Calculating the Thermal Resistance of a Heat Sink The circuit given below is a driver for a spark coil. Complete the following activities based on this circuit. 1. Implement the circuit in Multisim with the following parameters: Spark Coil: L1 = 50 μH, L2 = 500 mH (use Multisim ideal transformer). The air gap distance is 0.71 mm. Area of the conducting faces is 21.2 mm². R6 = Air gap resistance = 10^19 ohm·mm (air gap distance) / (Conducting Area). R6 = _____ Peta ohms. 2. Calculate the Dissipation Power of the POWER MOSFET device IRF510 using measurement probes in the Multisim simulation (the probe should be in the drain pin of the MOSFET device): P_d = V_rms I_rms = ________. ET3380: Module 1 Basic Principles of Electronic Power Conversion Lab 1.1 Handout. Replace the device IRF510 with IRF520N in the Multisim circuit. a. Calculate the Dissipation Power of the POWER MOSFET device IRF520N using measurement probes in the Multisim simulation (the probe should be in the drain pin of the MOSFET device): P_d = V_rms * I_rms = ________. 4. R_sa (thermal resistance from sink to ambient) is defined as: R_sa = (T_j - T_a) / P_d, where T_j is the junction temperature and T_a is ambient temperature. Using the device datasheet and Multisim calculations, complete the following table: T_a = 25°C. Device | P_d | P_d max | R_jc | R_cs | T_j | T_a | R_sa | IRF510 | IRF520N. 5. According to the table, which device will instantly burn once the circuit is powered on? Answer: ______________. 6. Using the file ET3380_Lab1.1_Heat_Sinks_TO220.xlsx, find a heat sink with a thermal resistance at natural convection closest to the R_sa calculated in item 4. Complete the table with Part Number, Manufacturer, Package, and Thermal Resistance at Natural Convection. ET3380: Module 1 Basic Principles of Electronic Power Conversion Lab 1.1 Handout 3 Activity 2. Calculating Fan CFM for Forced Air Cooling A fan may be necessary if the obtained R_sa exceeds the value from the heat sink. 1. Calculate the LFM (linear feet per minute) of the fan: Adjustment Factor = Rsa / (Heat Sink Thermal Resistance @ natural). LFM = _______. Using Table 3 from Bachman, interpolate to find the corresponding LFM value. 2. Using Table 2 from Bachman, which provides CFM per LFM, calculate the required CFM: CFM >= ________. 3. In the file ET3380_Lab1.1_Fans12V.xlsx, find a fan with airflow (CFM) close to this value. Review Questions 1. Does the transistor need a heat sink? Explain. 2. Where would you place the car contact switch in the circuit? What is the minimum car battery voltage needed? Would you need a fan for a few HV pulses? Provide explanations accordingly.