Direct HVDC Transmission from Series-Connected PV Modules
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Solution Overview
Problem
Existing photovoltaic power systems require multiple conversions of electrical voltage for long-distance high-voltage direct current transmission, leading to high investment costs and energy losses, as they need to convert DC voltage to AC and back to DC again, necessitating multiple inverters and a central transformer station on the generator side.
Innovation Solution
A photovoltaic device that generates a high DC voltage exceeding the dielectric strength of individual modules, allowing direct connection in series to form module blocks and strings, which are insulated and connected to a high-voltage direct current transmission line, eliminating the need for inverters and transformers on the generator side, with only a final conversion to AC on the consumer side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If multiple voltage conversions are performed (DC to AC to DC) for long-distance high-voltage transmission, then the transmitted power can reach distant consumers, but investment costs and energy losses increase significantly
Solution Approach 1:
The invention extracts and eliminates the intermediate AC conversion stage from the traditional DC-AC-DC transmission chain. By directly converting PV-generated DC voltage to high-voltage DC through series connection of modules, the system removes the unnecessary AC conversion step, thereby eliminating associated energy losses and reducing system complexity.
Solution Approach 2:
The invention performs preliminary voltage elevation by connecting photovoltaic modules in series before transmission begins. This preliminary action of generating high-voltage DC directly at the source eliminates the need for subsequent voltage conversions during transmission, reducing energy losses and simplifying the overall system architecture.
2Power
If multiple inverters and a central transformer station are installed on the generator side for voltage conversion, then high-voltage transmission is enabled, but investment costs increase
Solution Approach 1:
The invention extracts and removes the complex infrastructure of multiple inverters and central transformer stations from the generator side. By implementing direct series connection of PV modules to generate high-voltage DC, the system eliminates these expensive and complex conversion components while maintaining the capability for high-power transmission.
Solution Approach 2:
Instead of converting low-voltage DC to high-voltage DC through multiple intermediate steps (the conventional approach), the invention inverts the approach by directly generating high-voltage DC through series connection of modules. This inverted methodology simplifies the system architecture and reduces device complexity.
3Device complexity
If photovoltaic modules are connected in series to generate high DC voltage exceeding dielectric strength, then direct HVDC transmission is enabled, but insulation and safety requirements increase
Solution Approach 1:
The invention changes the voltage parameter by connecting modules in series to generate high-voltage DC that exceeds individual module dielectric strength. This parameter change enables direct HVDC transmission but simultaneously increases insulation requirements, which is an accepted trade-off for achieving the primary goal of simplified transmission architecture.
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
This solution significantly reduces system technology costs, minimizes energy losses, and enhances efficiency by generating high-voltage DC directly for transmission, requiring only a single conversion at the consumer end, thus optimizing energy delivery.
Implementation Method 1
a plurality of photovoltaic modules PVM which, connected in series and/or in parallel, generate a direct current voltage Udc in the high-voltage range
Data Source
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AI summary
The invention relates to a power supply system (SYS) and a corresponding photovoltaic device (PVE) which comprises a plurality of voltage-generating photovoltaic modules (PVM), said photovoltaic modules (PVM) being interconnected in parallel and/or in series to generate a DC voltage (Udc*) which exceeds the voltage resistance (Umodmax) of the photovoltaic modules (PVM) and is suitable for transmitting a high voltage DC. The power supply system (SYS) has a converter station (UFS) which can be connected to a power supply network (SVN) for consumers and comprises a high-voltage DC transmission path (HGUE) to transmit the DC voltage (Udc*) generated by the photovoltaic device (PVE) to the converter station (UFS).