AC motor control device and tangible computer readable storage medium

An AC motor control device, comprising:

• a torque feedback control unit configured to calculate a voltage phase of an output voltage of an inverter, which converts DC power into AC power and supply it to an AC motor, as a manipulated variable for feedback controlling a torque output by the AC motor;
• and
• a switching command generation unit configured to generate a switching command for driving the inverter based on the voltage phase and a voltage amplitude calculated by the torque feedback control unit;
• wherein
• the torque feedback control unit includes
• a torque estimation section configured to calculate an estimated torque based on an electrical angle detected by a rotation angle sensor,
• a torque controller configured to calculate a pre-limitation voltage phase so as to bring a torque deviation between a command torque and the estimated torque close to 0,
• a limit range setting section configured to set a voltage phase limit range in a voltage phase-torque map defined according to a system voltage that is a DC voltage input to the inverter and a rotation speed of the AC motor, and
• a voltage phase limit section configured to limit a pre-limitation voltage phase to a voltage phase limit range instructed by the limit range setting section, and
• the limit range setting section
• sets a primary limit range from a primary lower limit phase to a primary upper limit phase within an interval from a minimum torque phase to a maximum torque phase in the voltage phase-torque map,
• sets a phase obtained by adding a maximum offset error of the rotation angle sensor to a command phase, which is a phase corresponding to the command torque in the voltage phase-torque map, as a secondary upper limit phase, and calculates a phase obtained by subtracting a maximum amount of offset error of the rotation angle sensor from the command phase as a secondary lower limit phase, and
• sets a range from a larger phase of the primary lower limit phase or the secondary lower limit phase to a smaller phase of the primary upper limit phase or the secondary upper limit phase as a secondary limit range, and
• the voltage phase limit section limits the pre-limitation voltage phase to the secondary limit range.

A tangible computer readable storage medium storing a program configured for execution by at least one processor of an AC motor control device, wherein

• the AC motor control device includes
• a torque feedback control unit configured to calculate a voltage phase of an output voltage of an inverter, which converts DC power into AC power and supply it to an AC motor, as a manipulated variable for feedback controlling a torque output by the AC motor, and
• a switching command generation unit configured to generate a switching command for driving the inverter based on the voltage phase and a voltage amplitude calculated by the torque feedback control unit, and
• the torque feedback control unit includes
• a function of calculating an estimated torque based on an electrical angle detected by a rotation angle sensor,
• a function of calculating a pre-limitation voltage phase so as to bring a torque deviation between a command torque and the estimated torque close to 0,
• a function of setting a voltage phase limit range in a voltage phase-torque map defined according to a system voltage that is a DC voltage input to the inverter and a rotation speed of the AC motor, and
• a function of limiting the pre-limitation voltage phase to a voltage phase limit range,
• the program including instructions when executed by the at least one processor to carry out:
• setting a primary limit range from a primary lower limit phase to a primary upper limit phase within an interval from a minimum torque phase to a maximum torque phase in the voltage phase-torque map;
• calculating a phase obtained by adding a maximum offset error amount of the rotation angle sensor to a zero phase, which is the phase where the torque crosses zero in the voltage phase-torque map, as a secondary upper limit phase smaller than the primary upper limit phase, and calculating a phase obtained by subtracting a maximum offset error amount of the rotation angle sensor from the zero phase as a secondary lower limit phase larger than the primary lower limit phase;
• and
• setting a range from the primary lower limit phase to the secondary upper limit phase as a secondary limit range when the command torque is negative, and setting a range from the secondary lower limit phase to the primary upper limit phase as a secondary limit range when the command torque is positive;
• and
• operating the torque feedback control unit to limit the pre-limitation voltage phase to the secondary limit range.

A tangible computer readable storage medium storing a program configured for execution by at least processor of an AC motor control device, wherein

• the AC motor control device includes
• a torque feedback control unit configured to calculate a voltage phase of an output voltage of an inverter, which converts DC power into AC power and supply it to an AC motor, as a manipulated variable for feedback controlling a torque output by the AC motor, and
• a switching command generation unit configured to generate a switching command for driving the inverter based on the voltage phase and a voltage amplitude calculated by the torque feedback control unit, and
• the torque feedback control unit includes
• a function of calculating an estimated torque based on an electrical angle detected by a rotation angle sensor,
• a function of calculating a pre-limitation voltage phase so as to bring a torque deviation between a command torque and the estimated torque close to 0,
• a function of setting a voltage phase limit range in a voltage phase-torque map defined according to a system voltage that is a DC voltage input to the inverter and a rotation speed of the AC motor, and
• a function of limiting the pre-limitation voltage phase to a voltage phase limit range,
• the program including instructions when executed by the at least one processor to carry out:
• setting a primary limit range from a primary lower limit phase to a primary upper limit phase within an interval from a minimum torque phase to a maximum torque phase in the voltage phase-torque map;
• calculating a phase obtained by adding a maximum offset error of the rotation angle sensor to a command phase, which is a phase corresponding to the command torque in the voltage phase-torque map, as a secondary upper limit phase, and calculating a phase obtained by subtracting a maximum amount of offset error of the rotation angle sensor from the command phase as a secondary lower limit phase;
• setting a range from a larger phase of the primary lower limit phase or the secondary lower limit phase to a smaller phase of the primary upper limit phase or the secondary upper limit phase as a secondary limit range;
• and
• operating the torque feedback control unit to limit the pre-limitation voltage phase to the secondary limit range.