将PWM信号正确调制为正弦波形需要使用正弦脉宽调制(SPWM)技术。SPWM通过调整PWM信号的占空比,使其在一个周期内近似为正弦波形。以下是详细的步骤和示例代码,展示如何在STM32上实现SPWM。
1. 正弦查找表
首先,创建一个正弦波查找表,用于生成SPWM信号。查找表中的值表示正弦波在一个周期内的不同时刻对应的幅值。
c
#define SINE_TABLE_SIZE 256 // 查找表大小
// 正弦查找表
const uint16_t sineTable[SINE_TABLE_SIZE] = {
2048, 2098, 2148, 2198, 2248, 2298, 2348, 2397, 2447, 2496, 2545, 2594, 2642, 2691, 2738, 2786,
2833, 2880, 2926, 2972, 3018, 3063, 3108, 3152, 3195, 3238, 3281, 3323, 3364, 3405, 3445, 3484,
3523, 3561, 3598, 3635, 3671, 3706, 3740, 3773, 3806, 3837, 3868, 3898, 3927, 3955, 3982, 4008,
4033, 4057, 4080, 4102, 4123, 4143, 4161, 4179, 4195, 4210, 4224, 4237, 4249, 4259, 4269, 4277,
4283, 4289, 4293, 4296, 4298, 4299, 4299, 4298, 4296, 4293, 4289, 4283, 4277, 4269, 4259, 4249,
4237, 4224, 4210, 4195, 4179, 4161, 4143, 4123, 4102, 4080, 4057, 4033, 4008, 3982, 3955, 3927,
3898, 3868, 3837, 3806, 3773, 3740, 3706, 3671, 3635, 3598, 3561, 3523, 3484, 3445, 3405, 3364,
3323, 3281, 3238, 3195, 3152, 3108, 3063, 3018, 2972, 2926, 2880, 2833, 2786, 2738, 2691, 2642,
2594, 2545, 2496, 2447, 2397, 2348, 2298, 2248, 2198, 2148, 2098, 2048, 1998, 1948, 1898, 1848,
1798, 1749, 1700, 1651, 1602, 1553, 1505, 1456, 1408, 1361, 1313, 1266, 1219, 1173, 1127, 1082,
1037, 992, 948, 905, 862, 819, 777, 736, 695, 654, 614, 575, 536, 498, 461, 424,
388, 353, 319, 285, 252, 219, 188, 157, 127, 98, 70, 43, 16, 1, 0, 0,
0, 0, 0, 1, 16, 43, 70, 98, 127, 157, 188, 219, 252, 285, 319, 353,
388, 424, 461, 498, 536, 575, 614, 654, 695, 736, 777, 819, 862, 905, 948, 992,
1037, 1082, 1127, 1173, 1219, 1266, 1313, 1361, 1408, 1456, 1505, 1553, 1602, 1651, 1700, 1749,
1798, 1848, 1898, 1948, 1998, 2048
};
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