Table of contents
Square wave high frequency injection simulation
Generate code development board run
foreword
Recently, I changed a small motor, so I tried the simulation of square wave high-frequency injection to the experiment of code generation. The way of sine wave injection has been realized.
A brief summary of the simulation and code generation development board demonstration experiment of the high-frequency injection of the lower wave. The experimental hardware system is as follows:
Square wave high frequency injection simulation
On the basis of the previous pulse vibration high frequency injection, the sine wave injection is removed, the square wave injection method is changed, and the angle calculation is also somewhat different from the pulse vibration high frequency injection.
During the simulation process, from no load to a sudden step load, the current amplitude becomes larger
To judge whether the high-frequency injection is a square wave injection or a sine wave injection, you only need to look at the phase current wave, as follows
Square wave injection, the current waveform can be seen as a triangular harmonic superimposed on the fundamental wave
Sine wave injection, the harmonics of the sine wave are superimposed on the fundamental wave of the current waveform, as shown in the figure below
Angle estimation, where the Hall angle is compared with the angle calculated by high-frequency injection, and they are basically the same
Generate code development board run
Integrated in the Keil environment, you can adjust the parameters in the Watch window to see the effect
Add a small fan and work in the speed loop mode. Due to the injection of harmonics, the feedback speed fluctuates. The control angle in the figure below is calculated by HFI, and the Hall angle is used for comparison. The effect is the same as the simulation.
The following figure shows the phase current measured by the oscilloscope, which are square wave high-frequency injection and sine wave high-frequency injection, which are the same as the previous simulation effect
Square wave high frequency injection
Summarize
Regardless of the performance, the experiment of square wave high-frequency injection has been realized. The pulse vibration high-frequency injection and the current square wave high-frequency injection have been realized on the same motor before. Although both can operate, the vibration can be intuitively felt. The effect of pulse high-frequency injection is better than that of square wave high-frequency injection. Since the motor used is a small surface-mounted motor, the performance difference caused by the influence of the algorithm and the motor cannot be ruled out. In the same running situation, the noise of pulse vibration is obviously smaller than that of high-frequency square wave injection. It is also possible that the algorithm or parameters have not been optimized well, and you will find relevant literature for comparison later when you have time.