Recently, power management has become increasingly important in storage-centric infrastructures, where SSD arrays are emerging as major power consumers. In such environments, static storage power capping (SSPC) has been used to reduce the peak power consumption of SSD arrays by fixing the power states of individual devices, aiming to stay within constrained power budgets. However, SSPC does not account for workload I/O characteristics or internal SSD behaviors such as garbage collection. This often leads to over-capping, which degrades performance, or underutilization of available power. To address these limitations, we propose PACMAN, a power usageaware capping and management framework designed for the storage layer in all-flash storage servers. PACMAN dynamically reallocates SSD power caps in real time through predictive adjustments based on recent per-device power usage. Without relying on performance counters, PACMAN efficiently adapts to workload variability and optimizes performance and energy efficiency within a given power budget. PACMAN has been extensively evaluated using both the FIO benchmark and a realworld application, RocksDB. Compared with SSPC, PACMAN improved throughput by up to 41% and energy efficiency by up to 24%.