A DDS-Based Wait-Free Phase-Continuous Carrier Frequency Modulation Strategy for EMI Reduction in FPGA-Based Motor Drive

Abstract

In AC motor drives, the fixed-frequencies harmonic components of output voltage and current from the inverter with fixed frequency pulse width modulation (FFPWM) usually lead to electromagnetic interference (EMI). The spread spectrum clock generation (SSCG) is a widely used solution of this problem. Adjusting the switching frequency to reduce EMI is one kind of practicable scheme among SSCG methods. How to design an optimal or suitable modulation profile is a research emphasis of scholars and has been discussed in depth in many literatures. However, apart from modulation profile, the mode and quality of carrier are also important and can be improved. In most frequency modulation methods, due to the limitation of the conventional carrier generation mode, the implementation of the new frequency instruction has to wait to the termination of the last switching period. In order to eliminate the waiting state and design a simpler algorithm, this paper has proposed a wait-free phase-continuous carrier frequency modulation strategy (WPCFM) by combining the direct digital frequency synthesizer (DDS) theory and proper temporal planning of control interruptions. Besides, theoretical analysis of WPCFM including quantization error, frequency jitter, phase delay and voltage distortion have been finished. Moreover, compared with conventional methods, a more convenient, feasible and simpler field-programmable gate array (FPGA) based algorithm implementation method and the control structure of WPCFM are also introduced. Analysis shows that, although WPCFM causes a slight increase of the current ripple, it can solve the partial frequency nonuniform distribution problem of conventional method and it has potential value of applications in the wide band gap (WBG) motor drive systems. The effectiveness of the WPCFM is verified by several sets of EMI reduction experiments where classical periodic carrier frequency modulations are applied. 1

A Regulated Pulse Current Driver with Spread Spectrum Clock Generator

“…As observed from Figure 7a, the first envelope null is also located at about 20 MHz, which is the same as shown in Figure 5a, which verifies Equation (8). We zoom in Figure 7a to get Figure 7b with a spectral range up to 5 MHz.…”

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A Review of BLDC Motor: State of Art, Advanced Control Techniques, and Applications

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RFNet: Fast and efficient neural network for modulation classification of radio frequency signals

“…To report the cost of the inference, one can combine the amount of computations (the computation cost) and the amount of memory required to store the parameters for performing the inference (the memory cost) into a single metric referred to as the inference cost. This metric was introduced in a recent modulation classi ication challenge issued by Xilinx to propose a fast and small network 1 . The following shows the equation for the inference cost.…”

“…One of the methods to control data rates in wireless radio environments is to apply different modulation methods to the Radio Frequency (RF) signal. Prior to the demodulation of signal at the receiver's end, Automatic Modulation Classi ication (AMC) is used to identify the modulation method in various applications e.g., electronic countermeasures [1,2] and spectrum monitoring methods [3]. There are different methods to implement AMC.…”