Method for direct voltage saturation calculation and prevention of inverter voltage saturation

An electric vehicle comprising:

• an electric motor;
• an inverter providing a plurality of output signals for operation of the electric motor;
• and
• a controller in communication with the inverter and performing operations comprising:
• receiving a control signal comprising an instruction to operate the electric motor, the instruction comprising a specific command current value;
• determining an expected amplitude of a plurality of output signals for the inverter to provide for operating the electric motor;
• determining, as a function of the specific command current value-without using any measurement systems, a modulation index;
• calculating, based on the modulation index and a maximum allowable modulation index determined based on a current modulation strategy of the inverter, a saturated voltage modifier value indicating an amount of modification of the plurality of output signals required to prevent the expected amplitude from reaching a saturation value, the calculated saturated voltage modifier value limited to a maximum allowable value based on an application-specific design parameter;
• and
• modifying, based on the calculation, the specific command current value to operate the electric motor to prevent the expected amplitude from reaching the saturation value;
• wherein the specific command current comprises:
• a commanded quadratic current component value Iq,cmd;
• and
• a commanded direct current component value Id,cmd;
• and
• modifying the specific command current value comprises:
• determining a modified commanded quadratic current component value, Iq,cmd,modified, by calculating:
• Iq,cmd,modified=Iq,cmd×Ecompensator;
• wherein Ecompensator is the saturated voltage modifier value;
• determining a modified direct current component value, Id,cmd,modified, by calculating:
• Id
• ,
• cmd
• ,
• modified
• =
• Id
• ,
• cmd
• -
• Iq
• ,
• cmd
• 2
• ×
• Ecompensator
• ❘
• "\[LeftBracketingBar]"
• Id
• ❘
• "\[RightBracketingBar]"
• ⁢
• max
• ;
• and
• wherein |Id|max is a maximum potential value of the direct current component for the electric motor.