UPS Battery Chopper Control for DC Bus Voltage Suppression
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Solution Overview
Problem
Existing uninterruptible power supply devices require two batteries and two bidirectional choppers, leading to increased size, weight, and cost, with complex control mechanisms, and face challenges in suppressing voltage increases on the DC bus without returning regenerative power to the AC power supply.
Innovation Solution
An uninterruptible power supply device with a single battery and a bidirectional chopper, controlled by a microcomputer, manages charging and discharging based on state of charge (SOC) to suppress voltage increases and utilize regenerative power effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two batteries and two bidirectional choppers are used to separately manage power failure compensation and regenerative power recovery, then the reliability and functionality are improved, but the device size, weight, and cost increase
Solution Approach 1:
The patent merges the functions of two separate batteries (power failure compensation battery and regenerative power recovery battery) into a single battery system. The single bidirectional chopper manages both power failure compensation and regenerative power recovery operations, eliminating the need for duplicate components and reducing overall device weight while maintaining functional reliability
Solution Approach 2:
The single battery is designed to perform multiple functions: it compensates for power failures by providing backup power and recovers regenerative power from the load during regenerative operations. The bidirectional chopper also serves universal purposes by handling both charging and discharging operations for the same battery, making the system more compact and efficient
2Adaptability or versatility
If two batteries and two bidirectional choppers are used to separately manage power failure compensation and regenerative power recovery, then the functionality is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple control functions into a unified system. The single bidirectional chopper integrates power failure compensation control and regenerative power recovery control, reducing the number of control circuits and simplifying the overall system architecture while maintaining the ability to handle different operational modes
Solution Approach 2:
The control system is designed with universal control capabilities that can manage both power failure compensation and regenerative power recovery using the same battery and chopper. This multi-functional control approach reduces system complexity by eliminating redundant control circuits while preserving operational versatility
3Ease of manufacture
If regenerative power is returned to the AC power supply, then the energy recovery is simplified, but the DC bus voltage increases and energy is lost
Solution Approach 1:
Instead of returning regenerative power to the AC power supply where it would be lost, the patent converts this previously wasted energy into a useful resource by storing it in the battery. The bidirectional chopper enables the battery to charge from the DC bus during regenerative operations, transforming energy that would have been dissipated into stored energy that can be reused during power failures or subsequent regenerative operations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves a simple configuration that suppresses DC bus voltage increases and effectively utilizes regenerative power, extending battery life and reducing size, weight, and cost by integrating power failure compensation and regenerative power recovery.
Implementation Method 1
a converter that converts alternating-current (AC) power from an AC power supply into direct-current (DC) power and outputs the DC power to a DC bus
Implementation Method 2
an inverter that converts the DC power received from the DC bus into AC power and supplies the AC power to a load
Implementation Method 3
a first bidirectional chopper that transmits and receives DC power between the DC bus and a storage battery
Implementation Method 4
a charging operation to store the DC power received from the DC bus in a power storage device
Implementation Method 5
a discharging operation to output the DC power in the power storage device to the DC bus
Implementation Method 6
converts regenerative power generated by the load into DC power and outputs the DC power to the DC bus
Data Source
AI summary
A bidirectional chopper selectively performs: a charging operation to store DC power received from a DC bus in a power storage device; and a discharging operation to output DC power of the power storage device to the DC bus. An inverter converts the DC power received from the DC bus into AC power and supplies the AC power to a load, and converts regenerative power generated by the load into DC power and outputs the DC power to the DC bus. An SOC reference value is set for the power storage device, the SOC reference value being smaller than an upper limit value of a usable range of the SOC and larger than a lower limit value of the usable range. When an AC power supply is sound, a control device controls the bidirectional chopper such that the SOC of the power storage device reaches the SOC reference value.