IPM Synchronous Motor Pitch Drive Emergency Operation
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Solution Overview
Problem
Existing pitch drive devices for wind or water power plants face challenges with high maintenance costs, low power density, and limited torque at low voltages, making them unsuitable for dynamic applications and emergency operations.
Innovation Solution
A pitch drive device utilizing a permanent-magnet three-phase IPM synchronous motor with a DC voltage energy storage system, allowing for high torque production even at low intermediate circuit voltages, and incorporating a diode-based coupling unit to manage voltage peaks and improve electromagnetic compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC motors are used for emergency operation, then emergency travel capability is improved, but maintenance requirements increase and power density decreases
Solution Approach 1:
The patent replaces the traditional DC motor mechanical system with an AC motor system equipped with power electronics (rectifier and inverter). This substitution maintains emergency travel capability through alternative means (using AC power supply with rectification and inversion) while eliminating the maintenance-intensive DC motor components, thereby resolving the contradiction between reliability and ease of repair.
2Reliability
If DC motors are used for emergency operation, then emergency travel capability is improved, but power density decreases
Solution Approach 1:
The patent substitutes DC motors with AC motors that have inherently higher power density. The power electronics system (rectifier and inverter) enables the AC motor to deliver high torque during emergency operation, achieving both emergency travel capability and high power density simultaneously.
3Ease of repair
If AC machines are used, then maintenance-free operation and high torque capacity are achieved, but torque output decreases at low intermediate circuit voltages
Solution Approach 1:
The patent employs power electronics (rectifier and inverter) to dynamically adjust electrical parameters. During emergency operation at low intermediate circuit voltages, the inverter modifies the frequency and voltage supplied to the AC motor, enabling the motor to maintain high torque output despite the reduced input voltage, thus resolving the contradiction between maintenance-free operation and torque capability at low voltage.
4Force
If high current flow is forced at low voltage, then torque capacity is maintained, but inverter capability is exceeded
Solution Approach 1:
The patent uses the inverter to precisely control the electrical parameters supplied to the motor. Instead of forcing high current that would exceed inverter capabilities, the inverter adjusts voltage and frequency to optimize torque production within the inverter's power handling limits, maintaining torque capacity while respecting inverter constraints.
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 enhances the robustness and safety of rotor blade adjustment, enabling rapid emergency travel and efficient energy storage, reducing current transmission and moment of inertia, while minimizing power consumption and extending system reliability.
Implementation Method 1
An IPM synchronous motor with a rotor equipped with permanent magnets... can achieve a higher torque than a comparable conventional synchronous motor
Implementation Method 2
A coupling unit, in particular a diode-based coupling unit, for suppressing disruptive voltage peaks
Data Source
Figure 1
Figure 2
Figure 3a~3d
AI summary
The invention relates to a pitch drive device (10) capable of emergency operation for adjusting a rotor blade pitch of a wind or water power plant. The pitch drive device (10) comprises an inverter device (14) and a three-phase current drive motor. The drive motor is implemented as a three-phase IPM synchronous motor (12) (Interior Permanent Magnet). A direct current power storage device (20) can advantageously be substantially directly connected to an intermediate direct current circuit (18), at least for emergency operation, between a rectifier device (16) and the inverter device (14) for at least briefly supplying power to the synchronous motor (12), so that the IPM synchronous motor (12) can be operated at least briefly under speed control when the intermediate circuit voltage UZK is falling. The invention enables speed-controlled emergency operation of the pitch drive device at high torque when an intermediate circuit voltage UZK is falling in emergency operation, wherein the direct current energy storage device can, for example, improve the efficiency as an energy buffer, and reduce current transfer via the rotor slip ring.