反激变换器凭借拓扑结构简单、成本低、体积小等优点，被广泛应用在多路输出的场合。在多路输出反激变换器中，传统的单闭环控制只对主路进行反馈调节，而辅路未加控制，所以导致交叉调整率问题的产生。目前，交叉调整率在多路恒压输出场合已经得到了很好的改善，但在多路输出恒流源中，交叉调整率问题仍未得到有效解决。

为了改善多路输出恒流源的交叉调整率问题，对反激变换器工作时能量的转移情况进行详细的理论分析，提出了一种基于功率分配控制的策略，对电源期望输出功率进行预判，根据控制策略将电源期望输入功率合理地分配到各路输出，从根本上解决交叉调整率问题。具体实现方式是，首先保证所设计的多路输出反激变换器工作在完全能量转换模式，根据每一路的期望输出电流值和实时负载值计算出多路输出的总期望功率，并结合能量守恒原则，获得总期望输入功率；其次，利用该模式下能量的转移情况推导主开关和各路输出整流开关管的精确导通时间，通过控制反激变换器主开关管的导通时间控制电源的总输入功率，通过控制输出端整流开关管的导通时间合理地分配总输入功率，使电源的总输出功率等于总输入功率，每一路便可获得期望功率，从而获得期望输出电流。基于该控制策略设计的多路输出恒流源，具有低交叉调整率、输出电流均单独可控、电源稳定性高等优点。

根据设计要求，选取适当的电路参数并在Saber软件环境中对所提出的控制策略进行仿真，可知在该控制策略下，多路输出恒流源的交叉调整率在2%以内，与理论分析一致。以TMS320F280049C作为主控制平台，制作样机并进行了硬件测试，实验结果表明，三路输出的交叉调整率均小于2%，输出电流精度和负载调整率均达到研究目标。

Flyback converters are widely used in multi-output applications due to their advantages of simple topology, low cost, and small size. In the multi-output flyback converter, the traditional single closed-loop control only feedback regulates the main circuit, and the auxiliary circuit is not controlled, so it leads to the problem of cross regulation rate. At present, the cross regulation rate has been improved very well in the case of multi-channel constant voltage output,However, the problem of cross regulation rate has not been effectively solved in the multi-output constant current source.

In order to improve the cross regulation rate of the multi-output constant current source, a detailed theoretical analysis of the energy transfer during the operation of the flyback converter is carried out, and a strategy based on power distribution control is proposed to predict the expected output power of the power supply. According to the control strategy, the expected input power of the power supply is reasonably distributed to each output, and the cross regulation rate is fundamentally solved. The specific implementation method is as follows, Firstly,the designed multi-output flyback converter is guaranteed to work in the Discontinuous conduction mode, According to the expected output current value and real-time load value of each channel, the total expected power of the multi-channel output is calculated, and combined with the principle of energy conservation, the total expected input power is obtained; Secondly,the precise conduction time of the main switch and each output rectifier switch can be derived using the energy transfer in Discontinuous conduction mode. The total input power of the power supply can be controlled by controlling the conduction time of the main switch of the flyback converter. The total input power can be It is reasonably distributed by controlling the on-time of the output rectifier switch tube so that the total output power of the power supply is equal to the total input power, and each channel can obtain the desired power, thereby obtaining the desired output current.The multi-output constant current source based on this control strategy has the advantages of low cross regulation rate, individually controllable output current and high power supply stability.

According to the design requirements, select appropriate circuit parameters and simulate the proposed control strategy in the Saber software environment. It can be seen that under this control strategy, the cross regulation rate of the multi-output constant current source is within 2%, consistent with theoretical analysis.Using TMS320F280049C as the main control platform, prototypes were produced and hardware tests were conducted. The experimental results show that the cross regulation rate of the three outputs is less than 2%, and the output current accuracy and load adjustment rate have reached the research goals.