Two-Quadrant Controller Segmentation for Power Loss Reduction
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Solution Overview
Problem
Existing electric drive systems face inefficiencies due to conduction and switching losses in IGBT switches, and the size and inefficiency of three-phase autotransformers, which affect the overall performance and compactness of frequency converters.
Innovation Solution
A two-quadrant controller design that uses insulated gate bipolar transistors (IGBTs) and MOSFET transistors, with intermediate circuit capacitors acting as output capacitors, allowing for efficient power management and reduced component count, and incorporates a virtual resistance to damp resonant circuits without power losses, enabling the operation of two drives in series with improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If IGBT switches are used in the converter, then the converter can handle high voltages and powers, but conduction losses and switching losses increase, reducing efficiency
Solution Approach 1:
The patent divides the high-voltage DC link into two separate DC links with different voltage levels (first DC voltage and second DC voltage). This segmentation allows the system to use IGBTs for high-voltage switching while using MOSFETs for low-voltage high-efficiency conversion, thereby reducing overall power losses while maintaining high power handling capability.
Solution Approach 2:
The patent changes the voltage parameter by creating two distinct DC voltage levels. The first DC link operates at high voltage for power handling, while the second DC link operates at low voltage for efficient conversion using MOSFETs. This parameter change enables the system to optimize for both power capability and efficiency in different stages.
2Loss of energy
If MOSFET switches are used instead of IGBT switches, then efficiency increases and losses decrease, but the blocking voltage is limited to around 600 V
Solution Approach 1:
The patent segments the voltage conversion function into two stages: first stage uses IGBTs for high-voltage blocking (up to 700V or more), and the second stage uses MOSFETs for efficient low-voltage conversion (up to 600V). This segmentation allows each transistor type to operate in its optimal voltage and efficiency range.
Solution Approach 2:
The first DC link with higher voltage acts as an intermediary between the high-voltage source and the low-voltage MOSFET converter. This intermediate high-voltage DC link allows the system to bridge the gap between high-voltage requirements and MOSFET voltage limitations.
3Volume of moving object
If a step-down converter or one-quadrant converter is used to generate DC voltage from mains voltage, then the converter can be compact, but power losses increase and efficiency worsens
Solution Approach 1:
The patent uses a two-quadrant controller that can dynamically operate in both rectifying and inverting modes, allowing bidirectional power flow. This dynamic capability enables the system to recover regenerative energy and operate efficiently in both motoring and generating quadrants, reducing overall power losses while maintaining compact size.
Solution Approach 2:
The patent changes the operating parameters by implementing a two-quadrant controller that can switch between different operating modes (rectifying and inverting). This allows the system to adapt to different load conditions and maximize efficiency across all operating quadrants, reducing power losses compared to fixed-mode converters.
4Speed
If the switching frequency of power electronic switches is increased, then response time decreases and current ripple reduces, but switching losses increase
Solution Approach 1:
The patent segments the switching functions between two types of switches: IGBTs for high-voltage switching at lower frequencies (reducing switching losses), and MOSFETs for low-voltage high-frequency switching (maintaining fast response and low current ripple). This segmentation allows each switch type to operate in its optimal frequency range.
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 power losses and improves efficiency by halving the construction output of the two-quadrant controller, allowing for compact and cost-effective designs with high efficiency, especially when using MOSFET transistors and virtual resistance to manage current and voltage effectively.
Implementation Method 1
A first capacitor is arranged between the first node and the third node. A second capacitor is arranged between the third node and the second node.
Implementation Method 2
The modulation index a is set to be equal to the sum of the value 0.5 and the ratio of the product of the current flowing in the coil and a virtual resistance to the magnitude of the input voltage
Data Source
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AI summary
The actuator (300) has four nodes (301-304), where a collector (331) and an emitter (332) of a transistor (330) are connected with the first and fourth nodes, respectively. A cathode (341) and an anode (342) of a diode (340) are connected with the first and fourth nodes, respectively. A collector (351) and an emitter (352) of another transistor (350) are connected with the fourth and second nodes, respectively. A cathode (361) and an anode (362) of another diode (360) are connected with the fourth and second nodes, respectively. A coil (370) is arranged between the third and fourth nodes. The transistors are designed as Insulated gate bipolar transistors (IGBTs). Independent claims are also included for the following: (1) a method for operating a two-quadrant actuator (2) a drive circuit for an electric drive.