Method for Balancing the Movement of Mobile Masses in a Bi-Linear Electrodynamic Motor

A method for balancing the motion of the magnetized movable masses of a bilinear electrodynamic motor comprising two movable masses moving in opposite senses parallel to the axis (x-x) of the motor according to a reciprocating motion, the movable masses constituting two pistons aligned in one and the same compression chamber and oscillating in mechanical opposition, said method comprising the steps of:

• providing at least one first magnetic sensor and at least one second magnetic sensor which are able to deliver a first electrical signal (s1(t)) and a second electrical signal (s2(t)), respectively, that are representative of the motion of a first movable mass and of a second movable mass, respectively;
• recording an error signal (Δs(t)) equal to the difference between said first (s1(t)) and second (s2(t)) electrical signals and performing a harmonic analysis of the said error signal;
• applying a sinusoidal excitation signal (e1(t)) at a given frequency f0 to the first movable mass;
• iteratively applying N successive excitation signals (e2n(t)) to the second movable mass, an excitation signal of rank n (0≦n≦N−1) being equal to a Fourier series of order n of fundamental frequency f0, the term of order n of the said series being adjusted in amplitude and in phase so as to minimize the component at the frequency n·f0 of the said error signal;
• and
• taking the excitation signal (e2N-1(t)) obtained at the iteration of rank N−1 as excitation signal for the second movable mass.