Regenerative Rectifier Energy Converter for Braking Heat Dissipation
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Solution Overview
Problem
Existing electrical drive systems face inefficiencies and safety risks due to the inability of uncontrolled rectifiers to feed electrical energy back into the AC network, leading to high voltage and current flows that can damage components, and the use of costly braking resistors is often necessary to convert excess energy into heat, which is inefficient and complex.
Innovation Solution
An energy converter comprising a regenerative rectifier, inductor, and capacitors, with power semiconductor modules and a metallic device, allows efficient conversion of excess electrical energy into heat using eddy currents, safely managing energy feedback into the AC network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an uncontrolled rectifier is used to convert AC power supply into DC circuit, then cost is reduced, but electrical energy cannot be fed back into the AC network during braking or generator operation, causing high voltage and current that can destroy electrical components
Solution Approach 1:
The regenerative rectifier is designed to perform multiple functions: it can operate as a standard rectifier converting AC to DC for motor operation, and simultaneously function as an energy feedback system during braking or generator operation. The power semiconductor modules are controlled to enable bidirectional energy flow, allowing the same hardware to handle both motor drive and energy recovery modes without requiring separate braking resistor circuits.
2Reliability
If a braking resistor with power semiconductor chopper is used to convert excess electrical energy into heat energy, then component destruction is prevented, but the system becomes very expensive and difficult to operate
Solution Approach 1:
The invention merges the braking energy dissipation function with the existing regenerative rectifier circuit. The power semiconductor modules that are already present in the regenerative rectifier are utilized for both energy feedback to the AC network and for controlling energy conversion to heat when needed. This integration eliminates the need for separate braking resistors and choppers, reducing system complexity while maintaining component protection capabilities.
3Use of energy by moving object
If a regenerative rectifier is used to feed electrical energy back into the AC power grid, then energy efficiency is improved, but it cannot always be guaranteed that the power grid has the capacity to safely absorb the electrical energy
Solution Approach 1:
The control device continuously monitors the state of the AC network and the DC circuit, and adjusts the operation of the power semiconductor modules accordingly. When the AC network capacity is sufficient, energy is fed back to improve efficiency. When the network capacity is limited or unavailable, the control device automatically switches to converting excess energy to heat through the braking resistor, ensuring safe operation at all times.
Solution Approach 2:
The system dynamically adapts its energy management strategy based on real-time network conditions. The power semiconductor modules are controlled to switch between different operating modes: regenerative feedback mode when network capacity is available, and braking dissipation mode when it is not. This dynamic adaptation allows the system to maximize energy efficiency while maintaining safety under varying operational conditions.
4Temperature
If the power semiconductor switch is used to control current flow to the braking resistor, then excessive heating is prevented, but the system becomes expensive and difficult to operate
Solution Approach 1:
The power semiconductor modules in the regenerative rectifier are designed to perform multiple functions: they control energy feedback to the AC network during normal operation, and simultaneously control current flow to the braking resistor when energy dissipation is required. This multi-functionality eliminates the need for separate power semiconductor choppers dedicated solely to braking control, simplifying operation while maintaining precise temperature control of the braking resistor.
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 solution enables efficient and safe conversion of excess electrical energy into heat, minimizing component damage and optimizing energy usage by allowing simultaneous energy conversion and feedback, even when the AC network is unable to absorb the energy.
Implementation Method 1
the coil is electrically connected between the first center tap and the second center tap... during energy conversion using the coil electrical energy can be induced into the metallic device and converted into heat energy
Implementation Method 2
electrical energy can be converted into heat energy, e.g. by means of an ohmic resistor also known as a braking resistor
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to an energy converter (1) for converting (32) electrical energy into thermal energy, having a regenerative rectifier (4), a coil (11) and a first and a second capacitor (12, 13), wherein: the regenerative rectifier (4) is electrically connected to a DC voltage circuit (5) and is electrically connectable to a first AC voltage system (6); the regenerative rectifier (4) has a first bridge branch (7) with a first and a second power semiconductor module (8, 9); the first and second power semiconductor modules (8, 9) are connected in series and form a first centre-point tap (10); the first power semiconductor module (8) is electrically connected to a first DC voltage phase (15), and the second power semiconductor module (9) is electrically connected to a second DC voltage phase (16) of the DC voltage circuit (3); the first and second capacitors (12, 13) are connected in series and form a second centre-point tap (14); the first capacitor (12) is electrically connected to the first DC voltage phase (15), and the second capacitor (13) is electrically connected to the second DC voltage phase (16) of the DC voltage circuit (5); and the coil (11) is electrically connected between the first centre-point tap (10) and the second centre-point tap (14). The invention also relates to a converter (10) having the energy converter (1) and to a method of the energy converter (1).