Power supply system of electric-powered vehicle

Patent metadata

Field	Value
Publication number	US-2016129796-A1
Application number	US-201414897028-A
Country	US
Kind code	A1
Filing date	Jun 5, 2014
Priority date	Jun 11, 2013
Publication date	May 12, 2016
Grant date	—

Abstract

A hybrid vehicle can travel using outputs from an engine and a second motor-generator. A first motor-generator can generate electric power for charging a plurality of DC power supplies using the output from the engine during vehicle traveling or during a vehicle stop. A power supply system includes a power converter connected across the DC power supplies and an electric power line connected in common to the first and second motor-generators. A control device generates operation commands for the first and second motor-generators and the engine so as to ensure driving request power based on a vehicle traveling condition and charging/discharging request power for the DC power supplies as a whole. The setting of the charging/discharging request power is switched in accordance with an operation mode of the power converter.

First claim

1 . A power supply system in which a powertrain of an electric-powered vehicle configured to include a first motor-generator for generating vehicle driving force serves as a load, the power supply system comprising:
an electric power line electrically connected to said load; a plurality of DC power supplies; a power converter connected across said plurality of DC power supplies and said electric power line; and a control device configured to control operations of said load and said power converter, said load being configured to have a power generation mechanism for generating electric power for charging said plurality of DC power supplies during vehicle traveling or during a vehicle stop, in accordance with an operation command from said control device, said power converter including a plurality of switching elements and being configured to control a voltage of said electric power line by operating with one operation mode among a plurality of operation modes different in a manner of power conversion between said plurality of DC power supplies and said electric power line being applied, said control device including
a charging/discharging control unit configured to make a setting of charging/discharging request power for said plurality of DC power supplies as a whole based on conditions of said plurality of DC power supplies, and
an operation command generation unit configured to generate an operation command for said load so as to ensure driving request power based on a traveling condition of said electric-powered vehicle and said charging/discharging request power,
said charging/discharging control unit switching the setting of said charging/discharging request power in accordance with said operation mode.

2 . The power supply system according to claim 1 , wherein
said plurality of DC power supplies are implemented by a first DC power supply and a second DC power supply, said plurality of switching elements include
a first switching element electrically connected across a first node and said electric power line,
a second switching element electrically connected across a second node and said first node,
a third switching element electrically connected across a third node, electrically connected to a negative electrode terminal of said second DC power supply, and said second node, and
a fourth switching element electrically connected across a negative electrode terminal of said first DC power supply and said third node,
said power converter further includes
a first reactor electrically connected across said second node and a positive electrode terminal of said first DC power supply, and
a second reactor electrically connected across said first node and a positive electrode terminal of said second DC power supply.

3 . The power supply system according to claim 2 , wherein
said first DC power supply has a capacity higher than the capacity of said second DC power supply, said plurality of operation modes include
a first mode of executing DC voltage conversion in parallel between said first and second DC power supplies and said electric power line by controlling on/off of said first to fourth switching elements, and
a second mode of executing DC voltage conversion between said first and second DC power supplies connected in series and said electric power line by keeping said third switching element on and controlling on/off of said first, second and fourth switching elements, and
said charging/discharging control unit, in said first mode, sets said charging/discharging request power so as to bring SOC of each of said first and second DC power supplies close to a control target, and in said second mode, sets said charging/discharging request power so as to bring SOC of said second DC power supply close to the control target.

4 . The power supply system according to claim 3 , wherein
said plurality of operation modes further include a third mode in which said first to fourth switching elements are kept on/off to maintain the state where said first and second DC power supplies are connected in series with said electric power line, and said charging/discharging control unit, in said third mode, sets said charging/discharging request power so as to bring SOC of said second DC power supply close to the control target.

5 . The power supply system according to claim 4 , wherein said plurality of operation modes further include
a fourth mode of executing DC voltage conversion between one of said first and second DC power supplies and said electric power line by controlling on/off of said first to fourth switching elements, and maintaining the state where the other one of said first and second DC power supplies is electrically disconnected from said electric power line, and a fifth mode of keeping on/off of said first to fourth switching elements to maintain the state where one of said first and second DC power supplies is electrically connected to said electric power line and the other one of said first and second DC power supplies is electrically disconnected from said electric power line, and said charging/discharging control unit, in each of said fourth and fifth modes, sets said charging/discharging request power so as to bring SOC of said one of said first and second DC power supplies close to the control target.

6 . The power supply system according to claim 3 , wherein said control device forcedly selects said first mode when present SOC in said first or second DC power supply reaches a control upper limit value or a control lower limit value.

7 . The power supply system according to claim 1 , wherein said control device includes
a control arithmetic unit configured to calculate overall input/output power from said plurality of DC power supplies as a whole to the electric power line based on a deviation between a voltage detection value of said electric power line and a voltage command value, a power distribution ratio setting unit configured to switch a power distribution ratio between said plurality of DC power supplies in response to a change of said operation mode, a power command value arithmetic unit configured to set a power command value for each of said plurality of DC power supplies in accordance with said overall input/output power and said power distribution ratio, a current control unit configured to calculate, for each of said plurality of DC power supplies, a duty ratio for controlling output from each of said plurality of DC power supplies based on a deviation of a current detection value from a current command value obtained by dividing said power command value by an output voltage, and a pulse width modulation unit configured to generate on/off control signals for said plurality of switching elements based on control pulse signals respectively obtained in accordance with pulse width modulation by comparing said duty ratio calculated for each of said plurality of DC power supplies and a carrier wave.

8 . The power supply system according to claim 2 , wherein said control device includes
a control arithmetic unit configured to calculate overall input/output power from said first and second DC power supplies as a whole to the electric power line based on a deviation between a voltage detection value of said electric power line and a voltage command value, a power distribution ratio setting unit configured to switch a power distribution ratio between said first and second DC power supplies in accordance with a change of said operation mode, a power command value arithmetic unit configured to set a first power command value for said first DC power supply and a second power command value for said second DC power supply in accordance with said overall input/output power and said power distribution ratio,

Assignees

• Toyota Motor Co Ltd

Inventors

• Tomura Shuji
• Ishigaki Masanori
• Yanagizawa Naoki
• Okamura Masaki

Classifications

• B60W20/13

  in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion · CPC title

• H02J7/1423

  with multiple batteries · CPC title

• B60W20/00

  Control systems specially adapted for hybrid vehicles {(hybrid vehicle design, B60K6/00; electric vehicles B60L)} · CPC title

• H02J7/34

  Parallel operation in networks using both storage and other DC sources, e.g. providing buffering (H02J7/14 takes precedence) · CPC title

• B60W10/26

  for electrical energy, e.g. batteries or capacitors · CPC title