Motorola M68HC08 manual Where

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

BLDC Motor Control

The best commutation was get with Advance_angle: 60Deg*1/8 = 7.5Deg

which means Coef_HlfCmt = 0.375 at Running state with default s/w setting

Per_Toff[n+1] = Per_ZCrosFlt*Coef_Toff and Per_Dis minimum Coef_Toff = 0.375 at Running state, Per_Dis = 150 with default s/w setting

Per_ZCros0 <-- Per_ZCros[n] T_ZCros0 <-- T_ZCros[n] T2*[n] = T_ZCros[n] + HlfCmt[n]

•If no back-EMF zero crossing was captured during preset commutation period (T2P[n] then Corrective Calculation 1. is made:

T_ZCros[n] <-- CmtT[n+1]

Per_ZCros[n] = T_ZCros[n] - T_ZCros[n-1] = T_ZCros[n] - T_ZCros0 Per_ZCrosFlt[n] = (1/2*Per_ZCros[n]+1/2*Per_ZCros0)

HlfCmt[n] = 1/2*Per_ZCrosFlt[n]-Advance_angle = Coef_HlfCmt*Per_ZCrosFlt[n]

The best commutation was get with Advance_angle: 60Deg*1/8 = 7.5Deg

which means Coef_HlfCmt = 0.375 at Running state! Per_Toff[n+1] = Per_ZCrosFlt*Coef_Toff and Per_Dis minimum Per_ZCros0 <-- Per_ZCros[n]

T_ZCros0 <-- T_ZCros[n]

•If back-EMF zero crossing is missed then Corrective Calculation

2. is made:

T_ZCros[n] <-- CmtT[n]+Toff[n]

Per_ZCros[n] = T_ZCros[n] - T_ZCros[n-1] = T_ZCros[n] - T_ZCros0 Per_ZCrosFlt[n] = (1/2*T_ZCros[n]+1/2*T_ZCros0)

HlfCmt[n] = 1/2*Per_ZCrosFlt[n]-Advance_angle = Coef_HlfCmt*Per_ZCrosFlt[n]

The best commutation was get with Advance_angle: 60Deg*1/8 = 7.5Deg

which means Coef_HlfCmt = 0.375 at Running state! Per_ZCros0 <-- Per_ZCros[n]

T_ZCros0 <-- T_ZCros[n]

• Where:

T_Cmt = time	of the last	commutation
T2 = Time of	the Timer 2	event (for Timer Setting)
T_ZCros = Time of the last zero			crossing
T_ZCros0 = Time of the previous			zero crossing
Per_Toff = Period of the		zero crossing off
Per_ZCros = Period between zero			crossings (estimates required
commutation period)
Per_ZCros0 =	Pervious period between zero crossings
Per_ZCrosFlt	= Estimated	period	of commutation filtered
Designer Reference Manual			DRM028 — Rev 0
44	BLDC Motor Control		MOTOROLA

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