Motor drive control with excess current period timer resetting
AssigneeDenso Corporation
InventorsToru Itabashi, Kazunari Shirai
Life of this patent
Estimating the term…
Abstract
A microcomputer produces to a drive circuit drive command signals for starting to drive and braking a motor so that the position of a throttle valve is controlled to a target position. A current supplied to the motor is limited not to exceed a first current limitation value at the time of motor drive start and braking. When the current limitation continues for a predetermined time period, the current is further limited not to exceed a second current limitation value. The microcomputer detects switching of motor current supply direction. When the current supply direction is switched, a reset command signal is produced to reset a timer operation for a current limitation continuation determination.
Claims7
A motor drive apparatus comprising:
- a motor having an output shaft to which a driven object is coupled to be position-controlled;
- a drive circuit which supplies electric current to the motor;
- position detection means which detects a position of the driven object;
- control means which receives a position detection signal from the position detection means and produces a drive command signal to the drive circuit to control the position of the driven object to a target position, the drive command signal being for starting to drive the motor at rest and supplying the current in a reverse direction for braking;
- current detection means for detecting the current supplied to the motor;
- current supply restriction means for restricting the current supply to the motor when the current value detected by the current detection means is in a large current supply condition and the condition continues for more than a predetermined time period;
- and
- reset means for resetting a time counting operation of the predetermined time period of the current supply restriction means in response to a detection of switching of current supply directions caused between motor drive start and braking.
A motor control method for controlling a motor which drives a control object comprising:
- supplying an electric current to the motor to control a position of the control object, a direction of the current being reversed between a motor drive starting and a motor braking;
- limiting the current to a first level in each period of the motor drive starting and the motor braking;
- counting a time period in which the current is limited to the first level;
- limiting the current to a second level lower than the first level when the counted time period reaches a predetermined period;
- detecting a switching of direction of supply of the current;
- and
- resetting. an operation of counting the time period when the switching of direction is detected.
Dependencies are inferred from the claim text.