Patent ID: 9166516
Filing Date: 2015-10-20
Classification: B60L,H02P,Y02T

Abstract:
1. A motor drive apparatus driving at least one motor, comprising: a drive unit driving said at least one motor, said drive unit selectively making a switch between a PWM control mode in which a pulse-width-modulated voltage is applied to said at least one motor, and a rectangular-wave voltage control mode in which a phase-controlled rectangular-wave voltage is applied to said at least one motor; a voltage boost circuit provided between a DC power supply and said drive unit and performing a voltage boost so that a system voltage representing a voltage for said drive unit is equal to or higher than a voltage of said DC power supply; and a control device controlling said voltage boost circuit, said control device setting a target value of said system voltage based on an electric power loss of said drive unit and said at least one motor, said control device calculating said target value of said system voltage using a function expression generated, for each operating point of said at least one motor, by approximating a loss characteristic which represents change of said electric power loss with respect to change of said system voltage, by a quadratic expression or a linear expression of said system voltage, wherein said at least one motor includes first and second motors, said drive unit includes first and second drive circuits driving said first and second motors, respectively, and said control device calculates said target value of said system voltage using a third function expression generated by adding a second function expression to a first function expression, wherein said first function expression is generated, for each operating point of said first motor, by approximating a loss characteristic of said first motor and said first drive circuit with respect to change of said system voltage, by a quadratic expression or a linear expression of said system voltage, and said second function expression is generated, for each operating point of said second motor, by approximating a loss characteristic of said second motor and said second drive circuit with respect to change of said system voltage, by a quadratic expression or a linear expression of said system voltage.