Center-Tapped DC/DC Converter for Inverter Neutral Point Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing DC/DC conversion circuits in inverters face issues with neutral point voltage imbalance due to inconsistent capacitor parameters or external half-wave loads, leading to distorted output waveforms, reduced capacitor lifespan, and potential overvoltage, which are not effectively addressed by current hardware or software solutions.
Innovation Solution
A DC/DC conversion circuit with a transformer having a center tap connected to the neutral point, utilizing current loops controlled by switching devices to balance the neutral point voltage without additional components or complex control algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a neutral point voltage balancing bridge is added to balance the neutral point voltage, then the neutral point voltage balance is improved, but the device complexity and cost increase due to additional power components and inductors
Solution Approach 1:
The patent merges the neutral point voltage balancing function with the existing DC/DC conversion circuit by utilizing the center tap of the transformer and the switching devices already present in the circuit. The balancing is achieved by selectively controlling the switching devices to create current loops that transfer energy between capacitors, eliminating the need for a separate balancing bridge and its associated components.
Solution Approach 2:
The switching devices in the DC/DC conversion circuit are made to serve dual functions: power conversion and neutral point voltage balancing. By controlling these switches to create specific current loops, the same circuit components perform both the primary conversion function and the auxiliary balancing function, thereby avoiding additional hardware.
2Reliability
If a neutral point voltage balancing bridge is added to balance the neutral point voltage, then the neutral point voltage balance is improved, but the energy efficiency decreases due to additional power components
Solution Approach 1:
The patent merges the neutral point voltage balancing function with the existing DC/DC conversion circuit by utilizing the center tap of the transformer and the switching devices already present in the circuit. The balancing is achieved by selectively controlling the switching devices to create current loops that transfer energy between capacitors, eliminating the need for a separate balancing bridge and its associated components.
3Reliability
If a special control method is used to balance the neutral point voltage, then the neutral point voltage balance is improved, but the control complexity increases
Solution Approach 1:
The system uses the existing switching devices and circuit structure to automatically balance the neutral point voltage through controlled current loops. The control leverages the circuit's inherent capabilities rather than requiring external complex control mechanisms, allowing the system to self-regulate the voltage balance using its own components.
4Adaptability or versatility
If capacitor parameters are inconsistent or external half-wave loads are applied, then the inverter operates under normal conditions, but the neutral point voltage shifts causing waveform distortion and potential overvoltage
Solution Approach 1:
The control method monitors the neutral point voltage and dynamically adjusts the switching states of the DC/DC conversion circuit to maintain voltage balance. When voltage imbalance is detected, the controller modifies the current loop activation to transfer energy between capacitors, creating a feedback mechanism that continuously corrects voltage deviations caused by inconsistent capacitor parameters or external half-wave loads.
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
Achieves neutral point voltage balance in inverters, preventing waveform distortion and overvoltage while reducing equipment costs and control complexity.
Implementation Method 1
a transformer, where the transformer includes a primary winding and a secondary winding
Implementation Method 2
the third end of the primary circuit is connected to the center tap, to provide a current loop to balance a voltage between the first end and the third end of the primary circuit and a voltage between the second end and the third end of the primary circuit
Data Source
AI summary
A direct-current conversion circuit, which is used for providing direct-current conversion between a first direct-current voltage and a second direct-current voltage is described. The direct-current conversion circuit comprises: a transformer, which comprises a primary-side winding and a secondary-side winding, wherein the primary-side winding comprises a center tap, and a first primary-side winding and a second primary-side winding, which are respectively connected to the center tap; a primary-side circuit, wherein a first side of the primary-side circuit is connected to the primary-side winding, a second side of the primary-side circuit comprises a first end, a second end, and a third end, and a first direct-current voltage is provided between the first end and the second end of the primary-side circuit; and a secondary-side circuit, wherein a first side of the secondary-side circuit is connected to the secondary side winding.