- Rmit University 2121 6 Resistive Load A Diode Rectifier The Archive Data Set 1 Zip Contains 3 Oscilloscope Images Th 1 (62.16 KiB) Viewed 49 times
- Rmit University 2121 6 Resistive Load A Diode Rectifier The Archive Data Set 1 Zip Contains 3 Oscilloscope Images Th 2 (64.7 KiB) Viewed 49 times
- Rmit University 2121 6 Resistive Load A Diode Rectifier The Archive Data Set 1 Zip Contains 3 Oscilloscope Images Th 3 (64.57 KiB) Viewed 49 times
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RMIT University Ⓒ2121 School of Engineering • Draw the circuit topology of the rectifier for this operating condition using a schematic editor (e.g. PSIM, VISIO, etc.). Show the AC source, the rectifying devices, the DC load and all measurement locations. • Extract from the data set measurements of the average rectified DC output voltage, and plot this response as a function of the SCR firing angle. Compare this with the theoretical response for a full-wave three-phase rectifier supplying a resistive load. • Similarly, plot the measurements of the average load current as a function of the SCR firing angle, and compare this response with the theoretical response. • Compare against theory the firing angles at which rectifier conduction becomes discontinuous, and at which conduction ceases entirely. • Explain any discrepancies that exist between the theoretical rectifier responses and the measured data. 7. Resistive Inductive Load. a) Diode Rectifier The archive <Data Set 3.zip contains one oscilloscope image that captures the operation of a full-wave three-phase SCR rectifier supplying a series connected resistive and inductive load with the nominal parameters of 5002 and 200mH. The rectifier is supplied from a variac set to produce a nominal 100%, (rms) 50Hz AC source voltage. The measurements shown in these oscilloscope traces are as follows: • Channel 1 (Yellow) -Rectified DC Voltage using P5200 probe @ 500X attenuation. • Channel 2 (Green)- AC Supply Voltage (Vew) using P5200 probe @ 500X attenuation. • Channel 3 (Blue)-DC Load Current using A600 current probe @ 100mV/A. • Channel 4 (Magenta)-AC Supply Current (la) using A600 current probe @ 100mV/A. • Reference 1 (Orange) - AC Supply Voltage (Vas) using P5200 probe @ 500X attenuation and saved to R1. Analysis: • Draw the circuit topology of the rectifier for this operating condition using a schematic editor (e.g. PSIM, VISIO, etc.). Show the AC source, the rectifying devices, the DC load and all measurement locations. • Extract from the data set measurements of the line-to-line AC supply voltage (Vew), the rectified DC voltage, the AC supply current (IR), and the DC load current. Compare the waveforms for Is and loc against the results of the previous resistor only load condition in Section 6a). • How does the rectified DC output voltage compare with the measured value of Section 6a)? • Explain the effect of the DC load inductance on the input AC and DC load current waveforms. Explain any variations in DC output voltage compared to the results of Section 6a). Explain any discrepancies that exist between the theoretical rectifier responses and the measured data. b) SCR Rectifier The archive <Data Set_4.zip contains 9 oscilloscope images that capture the operation of a full-wave three-phase SCR rectifier supplying a series connected resistive and inductive load with the nominal parameters of 5002 and 200mH. The rectifier is supplied from a variac set to a produce a nominal 100%, (rms) 50Hz AC source voltage. Prof. McGan, Dr It Wilson EXT2274EEET2337 Online Laboratory 3 VI
RMIT University 2021 The measurements shown in these oscilloscope traces are as follows: • Channel 1 (Yellow)-Rectified DC Voltage using P5200 probe @ 500X attenuation. • • Channel 2 (Green) - AC Supply Voltage (Vaw) using P5200 probe @ 500X attenuation. Channel 3 (Blue) - DC Load Current using A600 current probe @ 100mV/A. Channel 4 (Magenta)-AC Supply Current (la) using A600 current probe @ 100mV/A. • Reference 1 (Orange) - AC Supply Voltage (VRN) using P5200 probe @ 500X attenuation and saved to RI. School of Engineering Analysis: • Draw the circuit topology of the rectifier for this operating condition using a schematic editor (e.g. PSIM, VISIO, etc.). Show the AC source, the rectifying devices, the DC load and all measurement locations. • Extract from the data set measurements of the line-to-line AC supply voltage (VW), the AC supply voltage (Vas), the rectified DC voltage, the AC supply current (IR), and the DC load current. Using Ves as the reference, compare these voltages and currents in terms of their magnitude and phase relationships. Note in particular how these waveforms change as a increases past 60, in comparison to the results of Section 6b). Determine the firing angle (a) at which conduction effectively ceases. • Extract from the data set measurements of the average rectifier DC output voltage, and plot this response as a function of the SCR firing angle. Compare this with the theoretical response for a full-wave three-phase rectifier supplying a resistive inductive load. • Similarly, plot the measurements of the average load current as a function of the SCR firing angle, and compare this response with the theoretical response. • Compare the DC output voltage waveforms as a increases past 60 to the response of a resistor only load system from Section 6a). • Explain any discrepancies that exist between the theoretical rectifier responses and the measured data. 8. Capacitor Output Filter a) Diode Rectifier - No DC Load Inductor The archive <Data Set 5.zip contains 2 oscilloscope images that capture the operation of a full-wave three-phase SCR rectifier supplying a 15002 resistive load with a parallel capacitive filter equal to 2200µF. The rectifier is supplied from a variac set to produce a nominal 100%, (rms) 50Hz AC source voltage. The measurements shown in these oscilloscope traces are as follows: • Channel 1 (Yellow)-Rectified DC Voltage using P5200 probe @ 500X attenuation. • Channel 2 (Green) - AC Supply Voltage (Vew and Vas) using P5200 probe @ 500X attenuation. • Channel 3 (Blue)-DC Load Current using A600 current probe @ 100mV/A. Channel 4 (Magenta)-AC Supply Current (la) using A600 current probe @ 100mV/A. • Reference 1 (Orange)-AC Supply Voltage (Vas) using P5200 probe @ 500X attenuation and saved to R1. Analysis: • Draw the circuit topology of the rectifier for this operating condition using a schematic editor (e.g. PSIM, VISIO, etc.). Show the AC source, the rectifying devices, the DC load and all measurement locations. Prof. McGan, Dr It Wilson ET2274EET2337 Online Laboratory 3 VI
School of Engineering • Extract from the data set measurements of the average rectifier DC output voltage. Compare this with the theoretical response for a full-wave three-phase rectifier supplying continuous current to the load. RMIT University Ⓒ2121 • Extract from the data set measurements of the line-to-line AC supply voltage (VRw), the AC supply voltage (Vas), the rectified DC voltage, the AC supply current (In), and the DC load current. Explore in particular the waveform of Ia. Is this current continuous or discontinuous? Examine Vas carefully, and compare it against Vas. Are the four notches identified in Section 6a) still present in these voltages? If not, explain why they are no longer present. Explain the waveform of Ix. including in particular the reasons for deviations in magnitude of successive pulses within a fundamental cycle. • Explain any discrepancies that exist between the theoretical and experimental rectifier responses. b) SCR Rectifier - DC Load Inductor The archive <Data Set 6.zip contains 5 oscilloscope images that capture the operation of a full-wave three-phase SCR rectifier supplying a 15002 resistive load with a parallel capacitive filter equal to 60μF, and a series connected inductor equal to 50mH. The rectifier is supplied from a variac set to produce a nominal 1001, (rms) 50Hz AC source voltage. The measurements shown in these oscilloscope traces are as follows: • Channel 1 (Yellow)-Rectified DC Voltage using P5200 probe @ 500X attenuation. • Channel 2 (Green)-AC Supply Voltage (Vew) using P5200 probe @ 500X attenuation. • Channel 3 (Blue) - DC Load Current using A600 current probe @ 100mV/A • Channel 4 (Magenta)-AC Supply Current (la) using A600 current probe @ 100mV/A. • Reference 1 (Orange) - AC Supply Voltage (VRN) using P5200 probe @ 500X attenuation and saved to R1. Analysis: • Draw the circuit topology of the rectifier for this operating condition using a schematic editor (e.g. PSIM, VISIO, etc.). Show the AC source, the rectifying devices, the DC load and all measurement locations. • Extract from the data set measurements of the average rectifier DC output voltage, and plot this response as a function of the SCR firing angle. Examine the waveforms of the DC output voltage at different firing angles (a). Identify the firing angle where the current becomes discontinuous. Note the magnitude of the plateau voltage when no rectifier current is flowing. • Explain the changes in the SCR DC link voltage waveform as the firing angle is increased past the point of discontinuous conduction. • Explain any discrepancies that exist between the theoretical and experimental rectifier responses. 9. Effect of Source Inductance a) Diode Rectifier The archive <Data Set 7.zip contains two oscilloscope images that capture the operation of a full-wave three-phase SCR rectifier supplying a load consisting of a 200mH inductor and a 1500 resistor. The rectifier is supplied from a variac set to produce a nominal 100%, (ms) 50Hz AC source voltage through a 15mH source inductance (for all three phases). The measurements shown in this oscilloscope trace are as follows: Prof. McG, Dr It Wilson ET2274EET2337 Online Laboratory 3 VI
RMIT University 2021 School of Engineering • Channel 1 (Yellow)-Rectified DC Voltage using P5200 probe @ 500X attenuation. Channel 2 (Green) - AC Supply Voltage (Vew) using P5200 probe @ 500X attenuation. Channel 3 (Blue) - DC Load Current using A600 current probe @ 100mV/A. Channel 4 (Magenta)-AC Supply Current (la) using A600 current probe @ 100mV/A. • Reference 1 (Orange) - AC Supply Voltage (Vex) using P5200 probe @ 500X attenuation and saved to R1. Analysis: • Draw the circuit topology of the rectifier for this operating condition using a schematic editor (e.g. PSIM, VISIO, etc.). Show the AC source, the rectifying devices, the DC load and all measurement locations. • Extract from the data set measurements of the average rectifier DC output voltage. Compare this with the results from Section 7a). Determine the width of the notches observed in Vas during one fundamental cycle. Using the measured notch width in VRN, estimate the input source inductance of the incoming AC supply, and compare it with the identified value from the test set front panel. Explain any discrepancies that exist between the theoretical rectifier responses and the measured data. b) SCR Rectifier The archive <Data Set 8.zip contains 10 oscilloscope images that capture the operation of a full-wave three-phase SCR rectifier supplying a load consisting of a 200mH inductor and a 1502 resistor. The rectifier is supplied from a variac set to produce a nominal 100%. (rms) 50Hz AC source voltage through a 15mH source inductance (for all three phases). The measurements shown in these oscilloscope traces are as follows: • Channel 1 (Yellow) - Rectified DC Voltage using P5200 probe @ 500X attenuation. • Channel 2 (Green) - AC Supply Voltage (Vew) using P5200 probe @ 500X attenuation. Channel 3 (Blue)-DC Load Current using A600 current probe @ 100mV/A. • • Channel 4 (Magenta)-AC Supply Current (la) using A600 current probe @ 100mV/A. • Reference 1 (Orange) - AC Supply Voltage (Vex) using P5200 probe @ 500X attenuation and saved to R1. The Data Set 8 oscilloscope traces also contain up to two duplicate measurements at the same SCR firing angle, but with horizontal cursors enabled to capture time measurements. Analysis: • Draw the circuit topology of the rectifier for this operating condition using a schematic editor (e.g. PSIM, VISIO, etc.). Show the AC source, the rectifying devices, the DC load and all measurement locations. • Extract measurements of the notch width in VR as the firing angle varies. Why does the notch width change as the firing angle is increased? Using the formula given in the background notes, calculate the source inductance. Also check and verify that: Voc=1.35V, (cosa+cos(a+y))/2 Explain any discrepancies that exist between the theoretical rectifier responses and the measured data. Prof. McG, Dr It Wilson EXT2274 EXT2337 Online Laboratory VI