Study on control strategy and dynamic performance of variable-frequency compressor for vehicle-mounted refrigerated containers

To improve the control performance of variable-frequency compressors for vehicle-mounted refrigerated containers, this paper takes the no-load refrigeration condition with a target temperature of 5 °C as the research object. Optimal linear regulation and PID control models for the variable-frequency compressor are established. The dynamic response, energy consumption, and temperature-control accuracy of the two strategies are compared through simulations and no-load transportation experiments. A start-stop control logic is introduced to mitigate overcooling under low loads. The results show that the optimal linear regulation achieves a faster cooling rate and lower energy consumption, while PID control provides better temperature stability. However, both strategies suffer from excess cooling capacity and continuous under-temperature in the later stage of low-load operation. With the start–stop strategy, the compartment temperature fluctuates slightly around the setpoint, with a maximum temperature error of approximately 1.2 °C, meeting the requirements of ordinary cold-chain transportation. The compressor frequently starts and stops at 0 °C due to low heat load, while it operates continuously at −10 °C with a high heat load and good cooling capacity matching. This study provides a reference for optimizing the control strategy of variable-frequency refrigeration systems in refrigerated containers.