PWM

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The block is used in the BDCM and implements PWM modulation inside the pulses coming from the selector of the inverter keys.

The figure below explains the dependency between the parameters of the triangular PWM reference signal and the values set in the block properties (Figure 1).

Рисунок 1. PWM triangular reference signal parameters

The six-channel signal "PWM" manages the IGBT bridge keys. The distribution of the output signals (VT1...VT6) when controlling the half-bridges of the three-phase inverter is shown in the figure (Figure 2).

Рисунок 2. Distribution of output signals

The block allows you to implement three types of PWM modulation:

PWM 1 (Figure 3):

• It can be used with sufficiently large winding inductances.
• The reactive currents are closed through the inverter power supply.

Рисунок 3. Type of PWM signals for the "PWM - 1" circuit

PWM 2 (Figure 4):

• Provides minimum current pulsations in the motor windings.
• Reactive currents are closed through the motor windings and inverter diodes.
• It provides a minimum of losses in the lower keys of the inverter.

Рисунок 4. Type of PWM signals for the "PWM - 2" circuit

PWM 3 (Figure 5):

• It can be used for bootstrap power supply of inverter key drivers.
• Provides minimum current pulsations in the motor windings.
• Reactive currents are closed through the motor windings and the inverter keys.

Рисунок 5. Type of PWM signals for the "PWM - 3" circuit