Speed controller for 3-phase brushless motor

摘要: PURPOSE:To improve the efficiency of a brushless motor capable obtaining an accurate speed signal without loss irregular rotation performance by comparing and amplifying neutral point voltage 3-phase stator coils with drive coil arbitrary phase. CONSTITUTION:A Vu which is obtained adding sinusoidal counterelectromotive rectangular produced via resistance U-phase 4-1 generated in specific period, no current Iu flows when both output transistors U1, U2 are interrupted OFF, becomes only signal. Then, voltages Vn compared amplified differential amplifier 9, thereby P. The P converted into control Vs responsive to frequency discriminator 10, inputted preamplifier 6, converts Vs, limiting base at part or all U1-W2.