To mitigate the adverse impact of communication latency, the direct current (DC) voltage of offshore converters is typically employed as input signals in existing communication-free frequency support schemes for offshore wind farms (OWFs). Nevertheless, the offshore DC voltage fluctuates with the output power of OWFs, and this distortion degrades the frequency support performance. To resolve this problem, an improved communication-free coordinated control (ICFCC) scheme for VSC-MTDC integrated OWFs is proposed. The ICFCC scheme incorporates the onshore frequency variation into the DC voltage deviation when frequency events occur. Additionally, an estimator is proposed to determine the onshore DC voltage at offshore VSC stations, enabling rapid frequency support and mitigating the distortion effect. Meanwhile, to enhance support performance, the frequency support power is distributed logically by adaptively adjusting droop coefficients, allowing more power to be injected via the station nearest to the disturbance point. Following frequency support, the offshore wind turbines will restore their rotor speed using asymptotic control to minimize a second frequency drop. Case studies are performed on the 4-terminal and 5-terminal test systems, respectively, considering parameter uncertainties and noise disturbance. Various control methods are compared to demonstrate the effectiveness of the ICFCC scheme.