An uninterruptible 3-phase power supply , UPS, comprising: an input configured to (i) receive first power from a utility source to power at least one load , and (ii) receive second power from the utility source, wherein the at least one load is separate from the UPS; an inverter configured to receive (i) when in a first mode, the first power and the second power, and (ii) when in a second mode, the second power, wherein the second power is used to power the inverter; a bypass circuit comprising a bypass switch and connected to the input, wherein, while the inverter is operating in the second mode, the bypass switch is in a closed state to supply the first power from the input to an output of the UPS such that the inverter is in an idle mode, wherein the bypass switch is in an open state when operating in the first mode; and a control module configured to, (i) detect a voltage at the output of the UPS, (ii) integrate the voltage to generate a first sum, and (iii) subsequent to completing a transition from the second mode to the first mode, adjust an output voltage of the inverter based on the first sum to balance the voltage of the UPS such that an integrated sum of a voltage signal out of the UPS is zero for at least one of (i) one cycle of the voltage signal, or (ii) a predetermined period, wherein the voltage of the UPS is provided based on the output voltage of the inverter, wherein the control module is configured to (i) determine the first sum at an end of a first portion of a cycle of the output voltage of the UPS, (ii) compare the sum to a reference sum, and (iii) based on the comparison, adjust the output voltage of the inverter during a second portion of the cycle of the voltage of the UPS. an input configured to (i) receive first power from a utility source to power at least one load , and (ii) receive second power from the utility source, wherein the at least one load is separate from the UPS; an inverter configured to receive (i) when in a first mode, the first power and the second power, and (ii) when in a second mode, the second power, wherein the second power is used to power the inverter; a bypass circuit comprising a bypass switch and connected to the input, wherein, while the inverter is operating in the second mode, the bypass switch is in a closed state to supply the first power from the input to an output of the UPS such that the inverter is in an idle mode, wherein the bypass switch is in an open state when operating in the first mode; and a control module configured to, (i) detect a voltage at the output of the UPS, (ii) integrate the voltage to generate a first sum, and (iii) subsequent to completing a transition from the second mode to the first mode, adjust an output voltage of the inverter based on the first sum to balance the voltage of the UPS such that an integrated sum of a voltage signal out of the UPS is zero for at least one of (i) one cycle of the voltage signal, or (ii) a predetermined period, wherein the voltage of the UPS is provided based on the output voltage of the inverter, detect a voltage at the output of the UPS, (ii) integrate the voltage to generate a first sum, and (iii) subsequent to completing a transition from the second mode to the first mode, adjust an output voltage of the inverter based on the first sum to balance the voltage of the UPS such that an integrated sum of a voltage signal out of the UPS is zero for at least one of (i) one cycle of the voltage signal, or (ii) a predetermined period, wherein the voltage of the UPS is provided based on the output voltage of the inverter, wherein the control module is configured to (i) determine the first sum at an end of a first portion of a cycle of the output voltage of the UPS, (ii) compare the sum to a reference sum, and (iii) based on the comparison, adjust the output voltage of the inverter during a second portion of the cycle of the voltage of the UPS. <EOS>