Description: 在C54X DSP下实现查找表功能，可查找sin函数一个周期的查找表!-under the C54X DSP Lookup Table function, sin function can be found in a cycle lookup table! Platform: |
Size: 6748 |
Author:张有鹏 |
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Description: 在C54X DSP下实现查找表功能，可查找sin函数一个周期的查找表!-under the C54X DSP Lookup Table function, sin function can be found in a cycle lookup table! Platform: |
Size: 6144 |
Author:张有鹏 |
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Description: 在sinx函数实现的时候，请注意以下几点：
假设输入数据x=tπ时
2. t的范围为(-1,...,1)，即输入角度为(-π,…, π)，对应在dsp中用（8000h,...,7FFFh）表示。根据sin函数的单调性，将(0——π/2)等分为128个间隔，计算出各个离散点的sin值存于表_SinTab，最后根据输入的t值查表找到最接近的值得到输出结果。
3. 判断sinx输出值的正负情况。t的范围为(-1,...,1)，对应在dsp中用（8000h,...,7FFFh）表示，可见最高比特表示角度x大小为(-π,…,0)或者(0,…, π)，因此可以由输入值的最高比特对第2步的数据进行处理：当最高比特为1，sinx=-sin (x̃ )，否则sinx=sin (x̃ )。
-When implemented in the sinx function, please note the following: Suppose the input data x = tπ Time 2. T the range of (-1 ,..., 1), which enter the angle (-π, ..., π), corresponds to the dsp using (8000h ,..., 7FFFh) said. According to the monotonicity of sin function will be (0- π/2) and so is divided into 128 intervals, calculated the value of each discrete point of sin exist in the table _SinTab, the final value of the input of t is worth look-up table to find the closest to the output. 3. Determine the output value of the positive and negative situations sinx. t in the range (-1 ,..., 1), corresponding to the dsp using (8000h ,..., 7FFFh) that can be seen that the maximum bit size of angle x (-π, ..., 0) or (0 , ..., π), so the maximum value can be entered on Step 2 bits of data for processing: When the highest bit is 1, sinx =- sin (x), or sinx = sin (x). Platform: |
Size: 2048 |
Author:雨儿 |
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Description: 为了验证仿真的情况，需要把仿真部分转换为代码。
对于逆变，产生相应的控制占空比一般有2种方式：
1.通过计算sin公式，实时计算出输出值，送入epwm发生器中。
其中分2种，一种是直接计算，这种方式在简单的境况下可以使用，但是考虑到计算量对DSP比较大，一般不采用。另外一种是使用TI公司提供的IQmaths函数库里的函数，可以极大减少运算时间。
2.离线读表法。
通过实验发现，如果调用IQMATH直接计算，需要60us。由于开关频率为10K,整个控制的时间限定在100us以内。直接读表，则时间在10us内。
若是要加上闭环控制获得比较好的效果，必然得采用离线读表方式。
-In order to verify the simulation situation, it is necessary to convert part of the simulation code. For the inverter to yield the corresponding duty cycle is controlled generally in two ways: 1. By calculating formula sin, real-time calculation of the output value, into epwm generator. Which divided into two kinds, one is directly calculated in this way in a simple situation can be used, but considering the amount of computation of DSP is relatively large, generally not used. Another is to use IQmaths function library functions provided by TI, can greatly reduce the computation time. 2. Offline reading table method. Experiments found that, if the call IQMATH direct calculation requires 60us. Since the switching frequency is 10K, the entire time-controlled limited to less than 100us. Direct meter reading, the time within 10us. If you want to add closed-loop control to get better results, must give way to off-line reading table. Platform: |
Size: 218112 |
Author:林晓冬 |
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