Drive system and drive control method

Patent metadata

Field	Value
Publication number	US-11046191-B2
Application number	US-201716344213-A
Country	US
Kind code	B2
Filing date	Aug 30, 2017
Priority date	Dec 28, 2016
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A drive system including: a battery; a power generation device (PGD) including a power generator (PG) mounted to an engine shaft and an inverter converting AC-voltage of the PG into DC-voltage; a drive device (DD) including a motor driving a driven component and an inverter performing bi-directional conversion between AC-voltage of the motor and DC-voltage; a switching device (SD) including a plurality of switches switching a connection of the battery and the PGD at both ends of the DD between a series connection (S-connection) and a parallel connection (P-connection) for connection; a reactor arranged between the battery and SD or between the PGD and the DD; and a controller controlling each of the SD, PGD, and DD, wherein the controller uses, when a speed of the driven component is being changed, the SD to fix the connection of the battery and PGD to S-connection or P-connection after alternately switching the connection between the S-connection and the P-connection.

First claim

The invention claimed is:

1. A drive system, comprising:
a battery;
a power generation device including:
a power generator mounted to a shaft of an engine; and
an inverter configured to convert an alternating-current voltage of the power generator into a direct-current voltage;

a drive device including:
a motor configured to drive a driven component; and
an inverter configured to perform bi-directional conversion between an alternating-current voltage of the motor and a direct-current voltage;

a switching device including a plurality of change-over switches configured to switch a connection of the battery and the power generation device at both ends of the drive device between a series connection and a parallel connection for connection;
a reactor arranged between the battery and the switching device or between the power generation device and the drive device; and
a control unit configured to control each of the switching device, the power generation device, and the drive device,
wherein the control unit includes processing circuitry
to use, when a speed of the driven component is being changed, the switching device to fix the connection of the battery and the power generation device to any one of the series connection and the parallel connection after alternately switching the connection between the series connection and the parallel connection; and

to use an efficiency map, in which an efficiency obtained by multiplying a revolution number of the motor and a torque of the motor by an efficiency of the engine, an efficiency of the power generator, and an efficiency of the inverter is defined in advance, to determine a revolution number of the engine based on a battery voltage of the battery.

2. The drive system according to claim 1 , wherein the switching device includes at least three change-over switches as the plurality of change-over switches.

3. The drive system according to claim 2 , wherein the processing circuitry is configured to change an engine revolution number of the engine based on a revolution number and a torque that are required for the motor and on the battery voltage.

4. The drive system according to claim 2 , wherein the processing circuitry is configured to stop, when the speed of the driven component decreases after the battery and the power generation device are connected in series, an operation of the inverter configured to convert the alternating-current voltage of the power generator into the direct-current voltage, and, under a state in which the inverter is kept being stopped, use the switching device to fix connection of the battery and the power generation device to the parallel connection after alternately switching the connection between the series connection and the parallel connection.

5. The drive system according to claim 1 , wherein the processing circuitry is configured to change an engine revolution number of the engine based on a revolution number and a torque that are required for the motor and on a battery voltage.

6. The drive system according to claim 5 , wherein the processing circuitry is configured to increase the direct-current voltage of the power generation device when the battery voltage decreases after the battery and the power generation device are connected in series.

7. The drive system according to claim 5 , wherein the processing circuitry is configured to increase the direct-current voltage of the power generation device when the battery voltage decreases after the battery and the power generation device are connected in parallel.

8. The drive system according to claim 1 , wherein the processing circuitry is configured to stop, when the speed of the driven component decreases after the battery and the power generation device are connected in series, an operation of the inverter configured to convert the alternating-current voltage of the power generator into the direct-current voltage, and, under a state in which the inverter is kept being stopped, use the switching device to fix the connection of the battery and the power generation device to the parallel connection after alternately switching the connection between the series connection and the parallel connection.

9. The drive system according to claim 1 , wherein the inverter configured to convert the alternating-current voltage of the power generator into the direct-current voltage includes a diode.

10. A drive system, comprising:
a battery;
a power generation device including:
a power generator mounted to a shaft of an engine; and
an inverter configured to convert an alternating-current voltage of the power generator into a direct-current voltage;

a drive device including:
a motor configured to drive a driven component; and
an inverter configured to perform bi-directional conversion between an alternating-current voltage of the motor and a direct-current voltage;

a switching device including a plurality of change-over switches configured to switch a connection of the battery and the power generation device at both ends of the drive device between a series connection and a parallel connection for connection;
a reactor arranged between the battery and the switching device or between the power generation device and the drive device; and
a control unit configured to control each of the switching device, the power generation device, and the drive device,
wherein the control unit includes processing circuitry
to control, when a speed of the driven component is being changed, the direct-current voltage of the power generation device to be equal to or lower than a threshold value set in advance, and then use the switching device to fix the connection of the battery and the power generation device to any one of the series connection and the parallel connection.

11. The drive system according to claim 10 , wherein the switching device includes at least three change-over switches as the plurality of change-over switches.

12. The drive system according to claim 11 , wherein the processing circuitry is configured to change an engine revolution number of the engine based on a revolution number and a torque that are required for the motor and on the battery voltage.

13. The drive system according to claim 10 , wherein the processing circuitry is configured to change an engine revolution number of the engine based on a revolution number and a torque that are required for the motor and on the batter voltage.

14. The drive system according to claim 10 , wherein the inverter configured to convert the alternating-current voltage of the power generator into the direct-current voltage includes a diode.

15. A drive control method, which is performed in a drive system including:
a battery;
a power generation device including:
a power generator mounted to a shaft of an engine; and
an inverter configured to convert an alternating-current voltage of the power generator into a direct-current voltage;

a drive device including:
a motor configured to drive a driven component; and
an inverter configured to perform bi-directional conversion between an alternating-current voltage of the motor and a direct-current voltage;

a switching device including a plurality of change-over switches configured to switch a connection of the battery and the power generation device at both ends of the drive device between a series connection and a parallel connection for connection; and
a reactor arranged between the battery and the switching device or between the power generation device and the drive device,
the drive control method comprising:
using, when a speed of the driven component is being changed,

Assignees

• Mitsubishi Electric Corp

Inventors

• Tan Yohei
• Miyama Yoshihiro
• Harada Shigeki
• Iezawa Masahiro

Classifications

• H02J2105/37

  exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV] · CPC title

• H02J7/855

  with circuits adapted for supplying loads from the battery · CPC title

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• B60Y2400/61

  Arrangements of controllers for electric machines, e.g. inverters · CPC title

• B60Y2200/91

  Electric vehicles · CPC title