Monitoring method with function of correlation-based system identification
A monitoring method with a function of correlation-based system identification applicable for a digitally controlled DC-DC converter system is revealed. The monitoring method includes a plurality of steps. After the system is operated in a steady state, input a pseudo random binary sequence signal into the system via a pseudo random binary sequence generator and store the pseudo random binary sequence signal and an output signal of a path to be monitored in a memory unit. Then perform a correlation analysis of data stored in the memory unit by a correlation analysis module and output an impulse response. Next obtain a frequency response of the impulse response by a discrete-time Fourier transform module. Finally, smooth the frequency response by an adaptive sliding window smoothing module so that a monitoring curve of the frequency response becomes smooth.
1. A monitoring method with a correlation-based system identification function applied to a digitally controlled DC-DC converter system comprising the steps of
step 1 : inputting a pseudo random binary sequence signal into a digitally controlled DC-DC converter system via a pseudo random binary sequence (PRBS) generator;
step 2 : storing the pseudo random binary sequence signal and an output signal of a path to be monitored into a memory unit;
step 3 : performing a correlation analysis of data stored in the memory unit by a correlation analysis module and outputting an impulse response;
step 4 : getting a frequency response in relation to the impulse response by a discrete-time Fourier transform (DTFT) module; and
step 5 : smoothing the frequency response by an adaptive sliding window smoothing (ASWS) module.
2. The method as claimed in claim 1 , wherein the digitally controlled DC-DC converter system is operated in a steady state.
3. The method as claimed in claim 1 , wherein after the step 3 , the method further includes a step 3 -A of truncating disturbance of the impulse response by an impulse response filter module.
4. The method as claimed in claim 3 , wherein the impulse response filter module works based on a method selected from the group consisting of an averaging impulse response method, a Gaussian window method and an impulse-response truncation (IRT) method.
5. The method as claimed in claim 4 , wherein the impulse response filter module works based on the impulse-response truncation method.
6. The method as claimed in claim 1 , wherein the pseudo random binary sequence signal is periodic.
7. The method as claimed in claim 1 , wherein the pseudo random binary sequence generator provides a process of minimizing an autocorrelation function R uu of the pseudo random binary sequence signal to a function δ.
8. The method as claimed in claim 1 , wherein the correlation analysis module provides a circular correlation analysis process.
9. The method as claimed in claim 1 , wherein width of a sliding window of the adaptive sliding window smoothing module is increased along with increasing frequency.
10. The method as claimed in claim 1 , wherein the digitally controlled DC-DC converter system includes a power converter module, an analog to digital converter module connected to an output end of the power converter module, a digital compensator connected to an output end of the analog to digital converter module, and a digital pulse-width modulation module connected to an output end of the digital compensator and the power converter module respectively.
11. The method as claimed in claim 10 , wherein the pseudo random binary sequence signal is input into the output end of the digital compensator and the output signal of the path to be monitored is an output signal of the analog to digital converter module; a frequency response of the power converter module is obtained after the step 5 being completed.
12. The method as claimed in claim 10 , wherein the pseudo random binary sequence signal is input into an input end of the digital compensator while the output signal of the path to be monitored is an output signal of the digital compensator; a frequency response of the digital compensator is obtained after the step 5 being completed.
13. The method as claimed in claim 10 , wherein the pseudo random binary sequence signal is input into an input end of the digital compensator and the output signal of the path to be monitored is the output signal of the analog to digital converter module; a frequency response of loop gain is obtained after the step 5 being completed.