Control device for converter and electrically powered vehicle provided with the same
A voltage control operation unit receives, from a subtraction unit, a value obtained by subtracting a detection value of a voltage from a voltage command value, and performs a control operation for setting the voltage to be equal to the voltage command value. The voltage control operation unit outputs the calculated control amount as a current command value. A current control operation unit receives, from a subtraction unit, a value obtained by subtracting a detection value of a current from a current command value, and performs a control operation for setting the current to be equal to the current command value. A driving signal generation unit generates a signal for driving a boost converter based on a duty command value received from the current control operation unit.
1. A control device for a converter, said converter being provided between a DC power supply and an electrical load device and boosting an output voltage to be not less than a voltage of said DC power supply,
said converter comprising:
a reactor having one end connected to a positive electrode of said DC power supply;
a first switching element connected between the other end of said reactor and said electrical load device;
a second switching element connected between the other end of said reactor and a negative electrode of said DC power supply; and
first and second diodes connected in anti-parallel to said first and second switching elements, respectively,
an operation of said first and second switching elements including a dead time for preventing said first and second switching elements from being simultaneously brought into conduction, and
said control device comprising:
a voltage control unit performing a control operation for adjusting said output voltage to a target voltage;
a current control unit performing a control operation for adjusting a current flowing through said reactor to a target current, using a control output of said voltage control unit as said target current; and
a signal generation unit generating a signal for driving said first and second switching elements based on the control output of said current control unit.
2. The control device for a converter according to claim 1 , wherein
said electrical load device includes an electric motor, and
said control device further comprises a voltage control cycle setting unit setting an operation cycle of said voltage control unit based on a cyclical electric power variation caused by rotation of said electric motor.
3. The control device for a converter according to claim 2 , wherein said voltage control cycle setting unit sets said operation cycle to be not more than one fourth of a cycle of said electric power variation.
4. The control device for a converter according to claim 1 , wherein
said electrical load device includes a first electric motor,
said control device further comprises a first variation estimation unit estimating a first variation amount showing a cyclical electric power variation amount generated by rotation of said first electric motor based on a torque and a rotation speed of said first electric motor, and
said current control unit performs the control operation using, as said target current, a value obtained by adding said first variation amount to the control output of said voltage control unit.
5. The control device for a converter according to claim 4 , wherein
said electrical load device further includes a second electric motor,
said control device further comprises a second variation estimation unit estimating a second variation amount showing a cyclical electric power variation amount generated by rotation of said second electric motor based on a torque and a rotation speed of said second electric motor, and
said current control unit performs the control operation using, as said target current, a value obtained by adding said first variation amount and said second variation amount to the control output of said voltage control unit.
6. An electrically powered vehicle comprising:
a DC power supply;
a driving force generation unit generating a driving force for a vehicle using an electric power supplied from said DC power supply;
the converter according to claim 1 provided between the DC power supply and said driving force generation unit and boosting an input voltage of said driving force generation unit to a value not less than a voltage of said DC power supply; and
the control device for a converter according to claim 1 .