Electric car drive system provided with hybrid battery and control method

In an electric car drive system having a car drive motor powered by a mounted direct current power supply, an inverter to convert the direct current power supply into an alternating power supply of variable voltage and frequency, a car driving three-phase alternating current motor, a signal generating means to generate signals for controlling said inverter, and a key switch;

• wherein said direct current power supply comprises:
• a power battery having secondary cells connected to said three-phase alternating current motor;
• a voltage increasing current;
• and
• an energy battery which comprises fuel cells generating substantially constant outputs at substantially all times and which is connected via the voltage increasing circuit to said power battery,
• the electric car drive system further comprising:
• battery current and voltage control means which controls said voltage increasing circuit based on the current or voltage of any one of said power battery, said three-phase alternating current motor and said inverter, and which keeps the voltage of said direct current power supply within a specified range, including charge control means which charges said power battery using said energy battery when the charge of said power battery is below a specified value when said key switch is turned off, and suspends charging of said power battery when said charge is equal to or greater than the specified value.

An electric car drive system comprising:

• an inverter to convert a direct current power supply from a mounted main power supply into an alternating power supply of variable voltage and frequency;
• a car driving three-phase alternating current motor;
• a current sensor and a speed sensor to sense current and speed, respectively, of said three-phase alternating current motor;
• alternating current command generating means to generate a three-phase alternating current command, based on a value of accelerator opening and an output from said speed sensor;
• a PWM signal generating means to generate a signal to control said inverter based on said three-phase alternating current command and current flowing to said three-phase alternating current motor;
• and
• a key switch;
• wherein said main power supply comprises:
• a main contactor;
• a power battery having secondary cells connected to said three-phase alternating current motor via said main contactor and said inverter;
• a voltage increasing circuit;
• and
• an energy battery which comprises fuel cells and which is connected to said power battery via said voltage increasing circuit;
• the electric car drive system further comprising:
• a current sensor to detect the current of said power battery and said energy battery;
• and
• battery current and voltage control means which controls said voltage increasing circuit, based on the current or voltage of any one of said power battery, said three-phase alternating current motor and said inverter and which keeps the voltage of said direct current power supply within a specified range, including charge control means which charges said power battery using said energy battery when the charge of said power battery is below a specified value and when said key switch is turned off, and which suspends charging of said power battery when said charge is equal to or greater than the specified value.

A drive control method for an electric car drive control system, wherein said electric car has a car drive motor powered by a mounted direct current power supply, a signal generating means to generate signals for the control of motor speed;

• wherein said direct current power supply is composed of:
• a power battery having secondary cells connected to said motor;
• a voltage increasing circuit;
• an energy battery which comprises fuel cells generating constant outputs at all times and which is connected to said power battery via said voltage increasing circuit;
• and a key switch to control turning on or off of the power and energy batteries;
• the drive control method for the electric car drive control system comprising the steps of:
• controlling said voltage increasing circuit, based on the current or voltage of any one of said power battery, said energy battery and said motor, to charge the power battery using said energy battery while keeping the voltage of said direct current power supply within a specified range by:
• (i) charging said power battery using said energy battery when the charge of said power battery is below a specified value while said key switch is turned off;
• and
• (ii) suspending charging of said power battery when said charge is equal to or greater than the specified value.