Instaspin_foc示例程序文件proj_lab10a.c中为什么在进行过调制的时候需要进行电流重构(current reconstruction algorithm)？

在Instaspin_foc示例程序文件proj_lab10a.c中有这样的函数调用：

// run the current reconstruction algorithm
SVGENCURRENT_RunRegenCurrent(svgencurrentHandle, (MATH_vec3 *)(gAdcData.I.value));

//! \brief The relationship between Vs, Vd, and Vq is: Vs = sqrt(Vd^2 + Vq^2). In this FOC controller, the
//! \brief Vd value is set equal to USER_MAX_VS_MAG*USER_VD_MAG_FACTOR. Vq = sqrt(USER_MAX_VS_MAG^2 – Vd^2).
//! \brief Set USER_MAX_VS_MAG = 1.0 for a pure sinewave with a peak at SQRT(3)/2 = 86.6% duty cycle. No current reconstruction is needed for this scenario.
//! \brief Set USER_MAX_VS_MAG = 2/SQRT(3) = 1.1547 for a pure sinewave with a peak at 100% duty cycle.Current reconstruction will be needed for this scenario (Lab10a-x).
//! \brief Set USER_MAX_VS_MAG = 4/3 = 1.3333 to create a trapezoidal voltage waveform.Current reconstruction will be needed for this scenario (Lab10a-x).
//! \brief For space vector over-modulation, see lab 10 for details on system requirements that will allow the SVM generator to go all the way to trapezoidal.

请问:

1、这里的电流重构(Current reconstruction)是什么意思？ 

2、为什么在进行过调制的时候需要进行电流重构？

3、电流重构算法(current reconstruction algorithm)调用的函数SVGENCURRENT_RunRegenCurrent(svgencurrentHandle, (MATH_vec3 *)(gAdcData.I.value));是怎么样的原理？