## 3 Direct CSI SVM Modulator
### Major Simulation Blocks Based on Top-Level Drawing
The modulation signal extracted from the reference space vector in sectors 1-6:  
Figure 11 shows how reference space vectors are converted into modulation signals (S1-S6). These blocks are critical for extracting modulation signals from the reference control inputs that define the desired current waveforms for the CSI. The extracted signals are needed to ensure that the output currents closely match the desired sinusoidal waveforms and to control the inverter's switching states. The figure depicts the way these blocks are used in the simulation and the method of converting the reference space vector into the necessary  
Figure 10: The PLECS Blockset main block and its internal subblocks are integrated within MATLAB/Simulink. See Figure 6 for the top-level Simulink diagram. Figure 9: Basic vector sector transposition block used to rotate base vectors for simplified sector identification. modulation signals. It is very important to obtain a properly working and efficient CSI system. This process affects the quality of the output current and the overall performance of the inverter. The modular design of the modulation method eliminates the compatibility problem for different CSI modulation designs and control strategies. This flexibility makes these blocks essential tools for studying and improving CSI modulation in power electronics applications. 8. The sequencer is based on Sawtooth PWM (unlike the previous method with triangular PWM) and implements the patterns shown in Figure 5a above:  
This sequencer and its blocks, as seen in Figure 12, use a sawtooth waveform where the PWM output duty cycles are computed from the intersection of the sawtooth with reference signals. The sequencer efficiently manages the duration for which each inverter switch remains active by varying the height of these reference signals, therefore enabling the creation of output waveforms that closely approximate desired sinusoidal forms. Figure 13 shows the modulation waveforms of the control inputs from the reference for generating the CSI's switching patterns, depicting correct sector transition and duty-cycle distribution. Figure 11: Modulating signal extraction blocks. Figure 12: Sequencer implementation based on Sawtooth PWM, enabling efficient control of inverter switching durations. Figure 13 (Appendix A) details the symmetric SVM switching sequences implemented in the CSI simulation model, where each sector (1-6) follows predefined combinations of active vectors (e.g., ab, ac) and zero states (aa, bb, cc) to synthesize reference currents with minimum THD. The sequences enforce symmetry (even vector distribution per switching period) and a fixed 200 ns overlap time (shaded) for safe commutation, directly validating the modular simulation approach. These patterns enable users to verify sector transitions against theoretical predictions (see Section 2), experimentally adjust dwell times, and benchmark THD performance across modulation techniques, while serving as a foundation for custom SVM implementations. The sector selector and the state machine:  
Figure 13 in Appendix A shows the detailed subblocks of the selector block. The sector selector block is quite important in SVM for a three-phase CSI in deciding which of the six sectors the reference space vector currently resides in. This identification is necessary to enable the correct inverter switching states to generate the desired output. Figure 8 shows the full design of the sector selector, in which a full finite state machine is shown. By coordinating the timing and sequence of inverter switching states, the state machine in SVM ensures the true synthesis of the desired current waveform for the highest performance and least distortion. The CSI circuit uses the same values as the VSI-derived CSI SVM modulator:  
The comparative analysis uses the same basic component values of the CSI circuit displayed in Figure 3 from the VSI-derived CSI SVM modulator.