US Patent No. 10,090,798

MACHINE LEARNING APPARATUS AND METHOD LEARNING PREDICTED LIFE OF POWER DEVICE, AND LIFE PREDICTION APPARATUS AND MOTOR DRIVING APPARATUS INCLUDING MACHINE LEARNING APPARATUS


Patent No. 10,090,798
Issue Date October 02, 2018
Title Machine Learning Apparatus And Method Learning Predicted Life Of Power Device, And Life Prediction Apparatus And Motor Driving Apparatus Including Machine Learning Apparatus
Inventorship Masato Watanabe, Yamanashi (JP)
Yasuyuki Matsumoto, Yamanashi (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 10,090,798

1. A machine learning apparatus that learns a predicted life of a power device of a motor driving apparatus that converts DC power into AC power by a switching operation of the power device to supply the AC power to an AC motor, the machine learning apparatus comprising:a state observation processor to sample a state variable indicative of a state of the motor driving apparatus, the state variable having an effect on the life of the motor driving apparatus, the state variable being one or more of: data regarding a number of times of switching of the power device, data regarding a junction temperature of the power device, and data regarding at least one of: presence and absence of a failure of the power device;
wherein data regarding the number of times of switching of the power device is obtained by the state observation processor in response to receiving a switching command for ON/OFF driving of the power device generated by the motor driving apparatus;
wherein data regarding at least one of presence and absence of the failure of the power device is obtained by the state observation processor in response to receiving the switching command for the power device generated by the switching operation of the motor driving apparatus and AC power output from the power device, the AC power output being detected by a current detector;
wherein data regarding the junction temperature of the power device is obtained by the state observation processor based on: a temperature of a fin cooling the power device detected by a first temperature sensor, ambient air temperature of the motor driving apparatus detected by a second temperature sensor, a value of current supplied to the AC motor from the motor driving apparatus and detected by the current detector, and a value of voltage applied to the AC motor from the motor driving apparatus,
the state observation processor being in communication with the first temperature sensor and the second temperature sensor to receive the measured temperature of the fin cooling the power device and the ambient air temperature,
the state observation processor being in communication with the current detector to receive the AC power output and/or the current supplied to the AC motor detected by the current detector; and
a learning processor in communication with the state observation processor, the learning processor to learn the predicted life of the power device based on the state variable;
wherein the learning processor:
determines a function for computing the predicted life of the power device, each function being associated with a reward obtainable by the learning processor,
determines the function corresponding to a maximum value of the reward, and
changes one or more operating and/or environmental parameters of the motor driving apparatus based on the predicted life of the power device.