Engineering Phase voltage and Line-Line voltage relation

AI Thread Summary
The discussion focuses on understanding the relationship between phase and line-to-line voltages in a circuit involving a wye transformer and a three-phase inverter. The user is attempting to apply Kirchhoff's Voltage Law (KVL) but is uncertain about their calculations and the circuit's configuration. It is noted that the phase voltages UVA and UVB should be equal at 120V, while the line-to-line voltage is represented as UAB. The complexity arises from the presence of switches that alter the circuit's behavior, requiring KVL to be applied for specific switch states. The user seeks clarification on their approach and the overall functionality of the circuit.
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Homework Statement
Find the phase voltage and Line-Line voltage relation
Relevant Equations
Kirchhoff voltage and current laws
The below is the diagram i want to find the phase and line-line voltage relation
1676305359954.png

I am finding difficulty in identifying the loop and applying the KVL.
One attempt is
U_{VA} - U_R - U_L -U_O - U_L - U_R = U_VB
U_{VA} - 2(U_R+U_L) = U_VB -> eq1

Is my attempt correct? i am not confident please help.
 
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UVA and UVB should actually be equal if this is a schematic of a wye transformer. They should both be 120V. The line to line voltage would be UAB.
 
Probably a 3Φ motor drive or inverter, since there are ideal DC sources in there. But it could be a rectifier, I guess. Much depends on the switches. Normally KVL would only be applied for a specific switch state since the network changes when switches change.

What is this circuit supposed to do? How are the switches controlled?
 
Yes it is inverter
SAtSBtSCtU_VAU_VBU_VCU_ABU_BCU_CAUaUbUc
100udcbus/2-udcbus/2-udcbus/2udcbus0-udcbus
010-udcbus/2udcbus/2-udcbus/2-udcbusudcbus0
001-udcbus/2-udcbus/2udcbus/20-udcbusudcbus
110udcbus/2udcbus/2-udcbus/20udcbus-udcbus
101udcbus/2-udcbus/2udcbus/2udcbus-udcbus0
011-udcbus/2udcbus/2udcbus/2-udcbus0udcbus
I want to calculate the voltages Ua, Ub, Uc
For the 1st case if i consider
1 0 0 the circuit will be as below
1676390674623.png


If i write KVL
a. 1 0 0
VDCBus/2 + Ua -Ub + VDCBus/2 = 0;
Ua - Ub + VDCBus=0 -> 1

b. 0 1 0
VDCBus/2 + Ub -Ua + VDCBus/2=0
-Ua + Ub + VDCBus = 0 -> 2

c. 0 0 1
VDCBus/2 + Uc - Ub + VDCBus/2 = 0 -> 3

Very confusing am i in correct direction? The document is user guide page 51.
 

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