Control device for electric motor and hydraulic pressure supply system

A control device for an electric motor for use in a hydraulic pressure supply system which comprises:

• a first pump;
• a second pump;
• the electric motor that drives the second pump;
• a check valve being installed at an upstream position relative to a junction pipe at which an outlet-side pipe of the first pump and an outlet-side pipe of the second pump meet each other, and preventing backflow from the first pump to the second pump;
• and a hydraulic pressure measurement circuit that measures a hydraulic pressure of the outlet-side pipe of the second pump at an upstream position relative to the check valve,
• the hydraulic pressure supply system supplying a hydraulic pressure to hydraulic-pressure receiving equipment from the junction pipe,
• the control device including a processor circuit configured to:
• control an operation of the second pump by manipulating a power-supply voltage or a power-supply current to the electric motor;
• start supplying electric power to the electric motor to thereby start drive of the second pump before the first pump stops operating;
• and
• limit the power-supply current to the electric motor to a predetermined first current or less during a time period between the start of the drive of the second pump and a time when the hydraulic pressure measured by the hydraulic pressure measurement circuit exceeds a prescribed outlet hydraulic pressure serving as an operation stop condition of the first pump.