
15. Three-Phase Motor Control Timer Function
The three-phase motor control timer function is enabled by setting the INV02 bit in the INVC0 register to 1 (three-
phase motor control function used). Timer B2 is used for carrier wave control, and timers A1, A2, and A4 for three-
phase PWM output (U, U, V, V, W, W) control. An exclusive dead time timer controls dead time. Figure 15.11 shows
an example of the triangular modulation waveform (three-phase mode 0). Figures
15.12 and
15.13 show the triangular
modulation waveforms (three-phase mode 1).
Figure 15.14 shows the sawtooth modulation waveform.
Figure 15.11
Triangular Wave Modulation Operation (Three-Phase Mode 0)
Dead time
DUB0 = 0
m
Triangular Waveform as a Carrier Wave (Three-phase mode 0)
Triangular wave
TB2S bit in the
TABSR register
Signal wave
Timer B2
NOTE:
1. Internal signals. See Three-Phase Motor Control Timer Function Block Diagram.
The above applies under the following conditions:
- INVC0 register: INV01 bit = 0 (ICTB2 counter is incremented by 1 when timer B2 underflows)
INV02 bit = 1 (Three-phase control timer function used)
INV03 bit = 1 (Three-phase control timer output enabled)
INV06 bit = 0 (Triangular wave modulation mode)
- INVC1 register: INV10 bit = 0 (Timer B2 underflows)
INV11 bit = 0 (Three-phase mode 0)
INV15 bit = 0 (Dead time enabled)
INV16 bit = 1 (Rising edge of the three-phase output shift register (U-, V-, W-phase)
- ICTB2 register = 01h (Timer B2 interrupt is generated every timer B2 underflow)
Timer A4 start trigger signal(1)
TA4 register
Reload register(1)
n
p
q
r
Timer A4 one-shot pulse(1)
INV14 bit in
INVC1 register = 0
("L" active)
Dead time
Transfer values to the three-phase shift register from registers IDB0 and IDB1
Rewrite registers IDB0 and IDB1
U-phase output signal(1)
U-phase
INV14 bit in
INVC1 register = 1
("H" active)
U-phase
IR bit in the TB2IC register
m
The following shows examples to change PWM output levels.
- Default value of the timer: TA4 = m (The TA4 register is changed whenever the timer B2 interrupt is generated.)
First time TA4 = m, second time TA4 = n, third time TA4 = n, fourth time = p, fifth time = p
- Default value of the registers IDB0 and IDB1: DU0 = 1, DUB0 = 0, DU1 = 0, and DUB1 = 1
They are changed to DU0 = 1, DUB0 = 0, DU1 = 1, and DUB1 = 0 when the sixth timer B2 interrupt is generated.
nn
pp
qq
DU0 = 1
DU1 = 0
DUB1 = 1
DUB1 = 0
DUB0 = 0
DU0 = 1
DU1 = 1
Set to 0 by an interrupt request acknowledgement or by program
m
n
p
q
r