Patent ID: 9709444
Date: 2017-07-18
CPC Classifications: B60K,B60L,B60W,G01K,H02M,Y02T

Claim:
1. A motor controller comprising: a switching element configured to convert output electric power of an electric power supply into motor-driving electric power; a temperature sensor configured to measure a temperature of the switching element; and a computer configured to extract a maximum point and a minimum point in a time-dependent change in the temperature of the switching element, the computer being configured to calculate a temperature difference between the maximum point and the minimum point adjacent to each other and being configured to calculate an estimated value of a heat stress to which the switching element is subjected based on each calculated temperature difference, wherein the computer includes a counter memory storing the number of occurrences of each bin in a histogram, wherein a width of the bin is defined by a magnitude of the temperature difference, wherein the computer is configured to increase the number of occurrences of the bin corresponding to each of the temperature differences stored in the counter memory by one for each of the calculated temperature differences, and wherein the computer is configured to calculate the estimated value based on the number of occurrences of the bin stored in the counter memory.