METHOD AND SYSTEM FOR CONTROLLING AN ELECTRIC MOTOR CONTROL INSTALLATION

• US 20170302199A1
• Filed: 04/12/2017
• Published: 10/19/2017
• Est. Priority Date: 04/14/2016
• Status: Active Grant

• Current Assignee: Schneider Toshiba Inverter Europe SAS (Toshiba Corporation)
• Original Assignee: Schneider Toshiba Inverter Europe SAS (Toshiba Corporation)
• Inventors: BOULHARTS, Hocine, MESSAOUDI, Mehdi, VIDET, Arnaud
• Granted Patent: US 10,305,399 B2
• Time in Patent Office: Days
• CPC Class Codes: H02M 1/0043 Converters switched with a phase shift, i.e. interleaved non-isolated DC/DC converters H02M3/1586
• CPC Class Codes: H02M 1/123 Suppression of common mode voltage or current
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 7/06 using discharge tubes without control electrode or semiconductor devices without control electrode
• CPC Class Codes: H02M 7/23 arranged for operation in parallel H02M7/2176 takes precedence
• CPC Class Codes: H02P 27/08 with pulse width modulation
• CPC Class Codes: H02P 5/74 controlling two or more ac dynamo-electric motors H02P5/46, H02P5/60 take precedence

Abstract

A control method implemented for an electric motor control installation, the control installation including a first converter having controlled switching arms for applying first voltage edges to a first electric motor connected to the first converter by first output phases, a second converter having controlled switching arms for applying second voltage edges to a second electric motor connected to the second converter by second outlet phases, the control method including a step of synchronising first voltage edges with second voltage edges in order to minimise the common-mode currents generated by the installation.

Claims

1. A control method implemented for an electric motor control installation, said control installation comprising:

a first converter having controlled switching arms for applying voltage pulses, each having a voltage rising edge and a voltage falling edge, to a first electric motor connected to said first converter by first output phases,

a second converter having controlled switching arms for applying voltage pulses, each having a voltage rising edge and a voltage falling edge, to a second electric motor connected to said second converter by second output phases,

for each voltage pulse, the voltage rising edge and the voltage falling edge are determined from pulse-width modulation of intersective type between an asymmetric type carrier and two modulants,

the control method featuring a pulse synchronisation step in order to minimise the common-mode currents generated by said installation,

said method comprising the pulse synchronisation step, over a switching period, comprises;

positioning pulses by determining, for each pulse, the two modulants required for its positioning,

determining, over a switching period, the modulants so that each rising edge of a voltage pulse to be generated on an output phase of the first converter always coincides with a filling edge of a voltage pulse to be generated on an output phase of the second converter.

2. The control method according to claim 1, wherein the pulse synchronisation step, over a switching period, further comprises:

synchronizing the voltage rising edges of the voltage pulses generated on the output phases of the first converter with voltage falling edges of the voltage pulses generated on the output phases of the second converter, and

synchronizing the voltage falling edges of the voltage pulses generated on the output phases of the first converter with voltage rising edges of the voltage pulses generated on the output phases of the second converter.

3. The method according to claim 1, wherein each pulse formed as a succession of states and wherein:

a pulse, designated 0-1-0, which corresponds to the succession of the logic state 0, the logic state 1 and the logic state 0, has a voltage rising edge followed by a voltage falling edge,

a pulse, designated 1-0-1, which corresponds to the succession of the logic state 1, the logic state 0 and the logic state 1, has a voltage falling edge followed by a voltage rising edge, and wherein;

the two modulants defining the 0-1-0 type pulse are linked by the following equation;

m₁=m₂+2α

wherein α

corresponds to the duty cycle maximum power and m1 and m2 are both said modulants of the 0-1-0 type pulse,

the two modulants defining the 1-0-1 type pulse are linked by the following equation;

m₃=m₄+2β

wherein β

is the duty cycle of the 1-0-1 type pulse,

the duty ratio β

of the 1-0-1 pulse being related to the duty cycle of the 0-1-0 pulse by the following equation;

β

=1−

α

4. The method according to claim 1, comprising a step for detecting modulants in overmodulation to determine a number of switching arms blocked in each converter.

5. The method of claim 4, further comprising a step for determining a number of possible synchronisations according to the number of switching arms blocked in each converter.

6. A control system implemented for an electric motor control installation, said control installation comprising:

a first converter having controlled switching arms for applying first voltage edges to a first electric motor connected to said first converter by first output phases,

a second converter having controlled switching arms for applying second voltage edges to a second electric motor connected to said second converter by second outlet phases,

for each voltage pulse, the voltage rising edge and the voltage falling edge are determined from pulse-width modulation of intersective type between an asymmetric type carrier and two modulants,

the system having a synchronisation software module of the first voltage edges with the second voltage edges in order to minimise the common-mode currents generated by said installation and wherein said synchronisation software module is adapted to;

position pulses by determining, for each pulse, the two modulants required for its positioning,

determine over a switching period, the modulants so that each rising edge of a voltage pulse to be generated on an output phase of the first converter always coincides with a falling edge of a voltage pulse to be generated on an output phase of the second converter.

7. The control system according to claim 6, wherein the synchronisation model is run in order to:

synchronise the voltage rising edges of the voltage pulses generated on the output phases of the first converter with voltage falling edges of the voltage pulses generated on the output phases of the second converter, and

synchronise the voltage falling edges of the voltage pulses generated on the output phases of the first converter with voltage rising edges of the voltage pulses generated on the output phases of the second converter.

8. The system according to claim 6, wherein each pulse formed as a succession of states and wherein:

a pulse, designated 0-1-0, which corresponds to the succession of the logic state 0, the logic state 1 and the logic state 0, has a voltage rising edge followed by a voltage falling edge,

a pulse, designated 1-0-1, which corresponds to the succession of the logic state 1, the logic state 0 and the logic state 1, has a voltage falling edge followed by a voltage rising edge, and wherein;

the two modulants defining the 0-1-0 type pulse are linked by the following equation;

m₁=m₂+2α

wherein α

corresponds to the duty cycle maximum power and m1 and m2 are both said modulants of the 0-1-0 type pulse,

the two modulants defining the 1-0-1 type pulse are linked by the following equation;

m₃=m₄+2β

wherein β

is the duty cycle of the 1-0-1 type pulse

the duty ratio β

of the 1-0-1 pulse being related to the duty cycle of the 0-1-0 pulse by the following equation;

β

=1−

α

9. The system according to claim 6, further comprising a module for detecting modulants in overmodulation to determine a number of switching arms blocked in each converter.

10. The system according to claim 9, further comprising a module for determining a number of possible synchronisations according to the number of switching arms blocked in each converter.