Drive system, fluid utilization apparatus, and air conditioner

A drive system comprising:

• a power inverter to supply power to a first synchronous motor and a second synchronous motor connected in parallel to each other;
• a first current detector to detect a first current flowing to the first synchronous motor;
• a second current detector to detect a second current flowing to the second synchronous motor;
• a processor;
• and
• a memory to store a program which, when executed by the processor, performs:
• a first magnetic pole position estimation process of estimating a first magnetic pole position of a rotor of the first synchronous motor, using a voltage command for driving the first synchronous motor and the first current;
• a second magnetic pole position estimation process of estimating a second magnetic pole position of a rotor of the second synchronous motor, using the voltage command and the second current;
• a control process of outputting the voltage command, using a torque current command, a magnetic flux current command, the first current, and the first magnetic pole position;
• a pulsating component extraction process of extracting at least one of a torque current pulsating component and an active power pulsating component, the torque current pulsating component being contained in a torque current flowing to the second synchronous motor, the active power pulsating component contained in active power consumed by the second synchronous motor;
• a first subtraction process of determining an angle difference that is a difference between the magnetic pole positions of the rotors of the first synchronous motor and the second synchronous motor, using the first magnetic pole position and the second magnetic pole position;
• and
• a magnetic flux current command determination process of determining the magnetic flux current command, using the pulsating component extracted by the pulsating component extraction process and the angle difference.