Practical Control of Electric Machines by Rubén Molina Llorente

Author:Rubén Molina Llorente
Language: eng
Format: epub
ISBN: 9783030347581
Publisher: Springer International Publishing

To generate the normal and its complementary pair PWM signals, it is sufficient to set a data value, for example, in the MTU3.TGRD register which will be transferred to the temporary register Temp1A (Fig. 7.22) and then to the MTU3.TGRB register. Figure 7.23 shows the operation of the normal and complementary PWM signal generation with a preset deadtime according to the value of MTU3.TGRB.

In this example, the zero output level indicates activated while the output level to one indicates deactivated. The output level is configurable using the TOCR1A.OLSP and TOCR1A.OLSN bits. If both are zero, a zero level means activated for both the normal and complementary signals. Otherwise, if they take the value of one, a high level means activated for both outputs. It is possible to observe that these bits allow the activation level to be configured separately for each of the outputs, being very useful when the high-side power switch is activated at the opposite level of the low-side power switch. In either case, these bits also indicate the level at which the output remains when the duty cycle is zero. Figure 7.24 shows the case where the TOCR1A.OLSP and TOCR1A.OLSN registers take the value of zero; that is, the activation is low. Also, it is possible to observe that just at the moment that these bits are configured, the PWM outputs take the configured value (initial output), and when the counters begin, the output level is already controlled by the MTU4.TGRA register for this channel.

Fig. 7.24 Initial output of PWM after and before of its configuration OLSP = OLSN = 0. Courtesy of Renesas

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