Motor driving device and motor driving method
AssigneeFanuc Corporation
InventorsYasuyuki Matsumoto, Masaya Tateda, Keitarou Inagaki
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Abstract
A motor driving device includes N units (N is a natural number equal to or greater than 2) of inverters configured to control N units of motors, respectively, a×N units (a is a natural number) of cables configured to allow connection between the N units of inverters and the N units of motors, respectively, and a PWM signal output unit configured to transmit a PWM signal to the N units of inverters. The N units of inverters and the a×N units of cables are divided into M groups (M≤N). The PWM signal output unit outputs the PWM signal for driving at least one inverter belonging to each group of the M groups so that the PWM signals have phase differences shifted by 360 degrees/M among the groups.
Claims4
A motor driving device comprising:
- N units of motors, the N being a natural number equal to or greater than 2;
- N units of inverters configured to control the N units of motors, respectively;
- a×N units of cables configured to allow connection between the N units of inverters and the N units of motors, respectively, the a being a natural number;
- a PWM signal output unit configured to transmit a PWM signal to the N units of inverters,
- a stray capacitance estimating unit configured to calculate added stray capacitances obtained by adding each stray capacitance of the N units of motors and each stray capacitance of the a×N units of cables, at least based on information on the N units of motors and information on the a×N units of cables;
- and
- a grouping unit configured to obtain M groups having an identical stray capacitance, based on the added stray capacitances calculated by the stray capacitance estimating unit, and prepare a table indicating a combination of at least motors and inverters included in each of the M groups, wherein M is a natural number equal to or less than N and equal to or greater than 2, wherein
- the PWM signal output unit outputs the PWM signal for driving at least one inverter belonging to each group of the M groups so that the PWM signals have phase differences shifted by 360 degrees/M among the groups, based on the table.
A motor driving method for controlling a motor driving device, the motor driving device comprising:
- N units of motors, the N being a natural number equal to or greater than 2;
- N units of inverters configured to control the N units of motors, respectively, the N being a natural number equal to or greater than 2;
- and
- a×N units of cables configured to allow connection between the N units of inverters and the N units of motors, respectively, the a being a natural number,
- the motor driving method comprising a step of:
- calculating added stray capacitances obtained by adding each stray capacitance of the N units of motors and each stray capacitance of the a×N units of cables, at least based on information on the N units of motors and information on the a×N units of cables;
- and
- obtaining M groups having an identical stray capacitance, based on the added stray capacitances calculated, and preparing a table indicating a combination of at least motors and inverters included in each of the M groups, wherein M is a natural number equal to or less than N and equal to or greater than 2, wherein
- PWM signals each for driving at least one inverter belonging to each group of the M groups have phase differences shifted by 360 degrees/M among the groups, based on the table.
Dependencies are inferred from the claim text.