Power supply control circuits for brushless dc (bldc) motors

A power supply control circuit of a three-phase brushless DC (BLDC) motor, the power supply control circuit comprising:

• means for calculating the DC current consumption IS based on three phase current signals ISh1 ISh2 and ISh3 of the BLDC motor;
• the means comprising:
• three shunt resistors RSh1, RSh2, and RSh3;
• three amplifiers;
• a summing amplifier;
• and
• a low pass filter,
• wherein the three amplifiers are configured to amplify and perform an offset correction of voltages VSh1, VSh2, and VSh3 that correspond to the currents ISh1, ISh2 and ISh3 across the three shunt resistors RSh1, RSh2, and RSh3,
• wherein the summing amplifier is configured to provide a summed voltage VShT,
• wherein the low pass filter is configured to provide a filtered voltage VO of the voltage VShT, and
• wherein the DC current consumption of the BLDC motor IS is calculated according to the following equation:
• I
• S
• =
• V
• O
• K
• wherein K=RTotal*GainTotal, RTotal is the equivalent resistance of resistors RSh1, RSh2 and RSh3, and
• wherein GainTotal is the total amplification factor of the three amplifiers.