DC Bus Voltage Control in Modular Power Conversion Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power conversion systems with integrated DC/DC converter, bidirectional inverter, and bidirectional DC/DC converter are difficult to modify, especially to add a power storage function, and lack effective control over power input and output to and from the DC bus.
Innovation Solution
The system is configured with separate first and second power converters, each with controllers, allowing easy modification and regulation of power input and output through DC/DC converters and bidirectional inverters, using threshold voltages to manage power flow and suppress inverse power flows without high-speed communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a converter transformer is used to convert power frequency AC voltage to a higher frequency AC voltage, then the output voltage can be stabilized against input voltage fluctuations, but the transformer requires a large installation space and takes a long time to respond to load changes
Solution Approach 1:
The patent replaces the mechanical converter transformer with an electronic power conversion system comprising a rectifier circuit, DC link, and inverter circuit. This substitution eliminates the need for large transformer components while achieving the same voltage conversion function with faster response to load changes and reduced installation space.
Solution Approach 2:
The patent changes the operating parameters by converting power frequency AC to high-frequency AC through the inverter circuit. This parameter change enables the use of smaller, lighter components while maintaining voltage conversion capability and improving response time to load variations.
2Reliability
If a converter transformer is used for voltage conversion, then output voltage can be stabilized, but the response time to load changes is slow
Solution Approach 1:
The patent replaces the slow-response mechanical transformer system with a fast-response electronic power conversion system. The rectifier-inverter configuration enables rapid adjustment of output voltage in response to load changes, eliminating the inertia and slow response characteristics of transformer-based systems.
Solution Approach 2:
The patent introduces dynamic control capability through the inverter circuit, which can rapidly adjust its switching characteristics in response to load changes. This dynamic response capability allows the system to maintain stable output voltage even under rapidly varying load conditions, unlike static transformer systems.
3Speed
If a commercial power converter is used, then power frequency AC can be converted to high-frequency AC, but high-frequency voltage fluctuations occur due to load changes
Solution Approach 1:
The patent implements feedback control by detecting the output voltage of the inverter circuit and adjusting the switching characteristics of the inverter based on the detected voltage and desired output voltage. This feedback mechanism compensates for high-frequency voltage fluctuations caused by load changes, maintaining stable output voltage while preserving fast frequency conversion capability.
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
Enables flexible system configuration, reduces initial costs, and effectively manages power flow, suppressing inverse power flows promptly and maintaining power equilibrium, while allowing integration of power storage capabilities.
Implementation Method 1
a switching element (423) that switches on and off in response to a control signal (403)
Implementation Method 2
an integrating circuit (424) that integrates the triangular wave signal (422) to thereby generate a sine wave signal (425)
Implementation Method 3
a power amplifier (426) that amplifies the sine wave signal (425)
Implementation Method 4
a comparison circuit (421) that compares an input voltage (401) with a reference voltage (402)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a power converter 20, a DC bus 30 is supplied with a DC power from a voltage conversion circuit 21 for regulating a voltage of a power output from a DC power supply 10, a voltage of the DC power being regulated by the voltage conversion circuit 21. An inverter 22 converts a DC power on the DC bus 30 into an AC power and supplies the AC power as converted to a power system 46. A controller 23 controls the inverter 22. When it is necessary to suppress an output, the controller 23 suppresses the AC power supplied by the inverter 22 to increase a voltage on the DC bus 30.