Patent ID: 8766578

Claim:
A method of driving a load via a brushless DC motor, comprising: receiving a desired motor velocity ω d ; receiving actual velocity ω and rotor position angle θ from said load; generating armature phase drive currents i* k , for a desired torque τ d from the desired motor velocity ω d , actual velocity ω and rotor position angle θ using a modified commutation law; amplifying the armature phase drive currents via a driver/amplifier; and applying the amplified armature phase drive currents i k to an armature of said brushless DC motor for inducing rotation of said rotor and thereby rotating said load; wherein the modified commutation law comprises calculating compensated Fourier coefficients c′ of a truncated (finite) Fourier series approximating the armature phase drive currents for said desired motor velocity ω d as a function of the actual velocity ωand transfer function of said driver/amplifier, wherein said modified commutation law further comprises: a) computing fixed Fourier coefficients c of said Fourier series at zero velocity; b) computing said compensated Fourier coefficients c′ at said desired motor velocity ω d ; c) computing the armature phrase drive currents i*k by modulating the desired torque τ d with said corresponding commutation functions u k (θ) according to i* k (τ d ,θ)=τ d u k (θ), ∀k=1, . . . , p and u ⁡ ( θ ) = ∑ n = - N N ⁢ c n ⁢ ⅇ j ⁢ ⁢ nq ⁢ ⁢ θ ; and d) returning to b).