초록 ▼

The invention provides a method for controlling a brushless motor, with windings connected in star (`wye`) formation, including the steps of periodically applying a supply voltage between first and second windings, detecting the presence of a current in a third winding, and an instant of cessation o

The invention provides a method for controlling a brushless motor, with windings connected in star (`wye`) formation, including the steps of periodically applying a supply voltage between first and second windings, detecting the presence of a current in a third winding, and an instant of cessation of that current, monitoring the value of a back emf induced in the third winding and detecting a zero crossing point of the back emf, timing a predetermined delay from the zero crossing point, and after the end of the delay, applying the supply voltage to other windings. The invention also provides a method for use with motors having windings connected in delta formation.

대표청구항 ▼

[ What is claimed is:] [1.] A method for controlling a brushless motor having a plurality of windings, each having a first end connected to a common node and each having a second end connectable to supply voltages, comprising the steps of:a) applying an upper supply voltage to said second end of eac

[ What is claimed is:] [1.] A method for controlling a brushless motor having a plurality of windings, each having a first end connected to a common node and each having a second end connectable to supply voltages, comprising the steps of:a) applying an upper supply voltage to said second end of each of a first subset of said windings, applying a lower supply voltage to said second end of each of a second subset of said windings, said second end of at least one winding being disconnected from said supply voltages and comprising a disconnected winding, said supply voltage applied to at least one of said first and said second subsets being periodically interrupted;b) detecting a current in said disconnected winding and detecting an instant of cessation of said current in said disconnected winding;c) monitoring a value of back emf voltage induced in said disconnected winding, said monitoring beginning at said instant of cessation of said current in said disconnected winding;d) detecting a zero crossing point of said back emf voltage with respect to one of said upper and said lower supply voltages;e) timing a predetermined delay from said zero crossing point detected; andf) removing said supply voltages from said second ends of said first and said second subsets of said windings at the end of said predetermined delay, then applying said upper supply voltage to said second end of each of a third subset of windings, applying said lower supply voltage to said second end of each of a fourth subset of windings, said second end of at least one winding remaining unconnected to said supply voltages.