12 SYNTHESIS OF DC AND LOW-FREQUENCY SINUSOIDAL AC VOLTAGES FOR MOTOR DRIVES, UPS, AND POWER SYSTEMS APPLICATIONS
12.1 INTRODUCTION
The importance of power electronics applications for motor drives (AC and DC), UPS, and in power systems was described in Chapter 11. In many of these applications, the voltage-link structure of Figure 12.1 is used, where our emphasis will be to discuss how the load-side converter, with the DC voltage as input, synthesizes DC or low-frequency sinusoidal voltage outputs. Functionally, this converter operates as a linear amplifier, amplifying a control signal, DC in case of DC motor drives, and AC in case of AC motor drives, UPS, and other utility-related applications. The power flow through this converter should be reversible.
FIGURE 12.1 Voltage-link system.
These converters consist of bidirectional switching power-poles, discussed in Chapter 3, two in the case of DC motor drives and single-phase AC applications, and three in the case of AC motor drives and three-phase applications. These are shown for DC and AC motor drives in Figures 12.2a and 12.2b, respectively.
FIGURE 12.2 Converters for DC and AC motor drives.
12.2 BIDIRECTIONAL SWITCHING POWER-POLE AS THE BUILDING BLOCK
In buck and boost DC-DC converters, discussed in Chapter 3, implementation ...
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