You can find my comments in the attached file.

This paper proposes two MBC-based IPC techniques to achieve a trade-off between DEL reduction and pitch actuation by using a reference tracking IPC based on the estimation of original (non-IPC) blade loads. The l-infinity method uses individual controllers to mitigate tilt and yaw axes loads separately, whereas the l-squared technique projects the magnitude of the blade loads on to the radial axis and uses a single controller to reduce blade loads. The two controllers are compared against a baseline at 15 m/s for laminar and turbulent flows, varying reference loads and varying horizontal and vertical shear.

Overall, this is a thorough and well-written paper that makes a worthy contribution to wind turbine control research. The paper is structured well and easy to follow along. Below are some suggestions that may further improve the quality of the paper.

1. The paper provides a sufficient literature review of input-constrained, output-constrained and fatigue-constrained IPC techniques. It also clearly differentiates the proposed work from the literature. Further, it quantifies the performance of the proposed controllers. However, it is difficult to place the performance of the proposed control techniques with respect to one in the literature review. Providing the key metrics from past research that can be comparable to the proposed techniques will help place performance in perspective.
2. It would help to comment on the robustness of the proposed techniques. Especially, the robustness of the original load estimator to varying turbulence intensity, varying wind speed and varying wind shear. In particular, is the Jacobian in equation 15 dependent on wind speed or collective blade pitch angle? What would be the required procedure if the controller is to be designed for the entire full-load operating region as opposed to a single wind speed. Does higher wind turbulence than what was tested affect the performance of the original load estimator and the reference sign/angle output? While horizontal and vertical wind shear is varied, it is not clear if low overall wind shear is tested. In particular, is equation 14 stable when the original tilt and yaw moments are non-zero but small.

Minor comments:

1. Line 78: Unclear what the difference between pitch actuation and actuator activity is
2. Lines 126-129: the mapping of nP harmonics is confusing, please elaborate on this.
3. Line 138: The M_b being bold is confusing as M_b is a scalar component of M_R (line 144)
4. Line 155: denotes pitch angles in non-rotating frame sound repetitive within the sentence.
5. Line 164: Please confirm the T^-1 transform is correct with all cosines.
6. Line 216: subscript is omitted can be mentioned earlier?
7. In Fig 5: Clarify what the bands in the legend or the figure description, this is clarified to be one std dev. much later in the text.
8. Line 283: For this to be true the units in Fig. 5 should be MNm?
9. Line 286: Comment on why the DEL increases with higher bandwidth?
10. Line 345: radial axis* ?
11. Line 462: There are two single-line paragraphs here.
12. Line 481: The diminishing slope is hard to see, maybe mention or provide a zoomed overlay in Fig. 14