In designing inverter-type EPS (Emergency Power Supply) power supplies, there are several technical problems and faults that are usually encountered. Hereinafter, we will discuss the issues, analyze the causes, and offer corresponding solutions.
- Problem Description: Bias magnetism and a weak anti-unbalance design are the main symptoms that result in a low pre-pulse voltage before driving.
- Cause Analysis: Software bugs are also one of the major reasons causing this phenomenon. To solve this problem, the circuit design should be optimized to enhance the anti-interference capability, and at the same time, the software algorithm should be enhanced to ensure the driving signal is stable.
- Problem Description: So many EPS power supplies that are controlled by single-chip microcomputers are available that it is difficult to obtain better protection levels.
- Cause Analysis: On the other hand, small-capacity EPS products that are traditional UPS-based have mature manufacturing processes and comparatively stable performance. To address such issues, the system's reliability and protection functions can be enhanced by raising the level of hardware design and adopting more mature control strategies.
- Problem Description: Three-phase EPS has an issue regarding its behavior when subjected to unbalanced loads.
- Cause Analysis: This is mainly due to the fact that the design fails to follow the practice of independent control and output for every stage. For the sake of improvement, it is suggested that three Y-connected inverter transformers with independent designs are employed to enhance the capability to accept unbalanced loads.
- Problem Description: Failures of small-sized EPS power supply are mainly attributed to the main control board with some problems like current loop and slow dynamic response rate.
- Cause Analysis: Through redistributing the control function, enhancing the isolation protection measures, strict designing of the single-chip microcomputer system, and optimizing the comparison reference circuit, the incidence of these faults can be effectively reduced.
Problem Description: Although advanced battery management systems such as the ABM mode and temperature-compensated charging are very helpful in extending the life of batteries, issues may arise if the charging circuit design is not suitable or the material selection is unreasonable.
- Cause Analysis: It is advisable to use the mature constant current limited voltage mode and independent float charging mode for charging, since this would be able to guarantee the safety and stability of charging.
- Solution: Adopt a functional modular design, i.e., separate the inverter, charging, monitoring and other functional modules to form a modular structure. Not only is maintenance simplified but also the system reliability is enhanced to a great extent. 7. Use the EPS power supply according to the load characteristics. - Problem Description: Different load types have different EPS power supply requirements. - Solution: Develop suitable EPS power supply schemes according to the particular characteristics of inductive, capacitive, resistive, and nonlinear loads. Particular attention should be paid to matching the output current of the inverter bridge and the load current so that the power supply can continuously sustain different kinds of loads. As we can see from the analysis above, most issues of inverter EPS power supply design can be solved quite well through optimization of the design process, enhancement of hardware quality, and improvement of software algorithms. Meanwhile, taking into account the demands of real application conditions fully is the assurance of the efficient operation of the EPS power supply system.
