Motor Gate Drive Power Redundancy for Active Short Circuit
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Solution Overview
Problem
In motor control systems for electric vehicles, a single-point power source failure prevents the gate drive unit from performing a three-phase active short circuit, leading to potential damage from motor energy backflow and unexpected braking torque.
Innovation Solution
A redundant power source arrangement with independent gate drive circuits and power supply units for each phase of the inverter bridges, utilizing high-voltage and low-voltage battery power sources with conversion circuits, ensuring reliable three-phase active short circuit even if one power source fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-point power source is used to power the gate drive unit, then the system architecture remains simple and costs are reduced, but the system reliability deteriorates because the gate drive unit cannot perform three-phase active short circuit when the power source fails
Solution Approach 1:
The power source system is segmented into two independent power sources: a first power source (high-voltage battery) and a second power source (low-voltage battery). Each power source independently powers separate gate drive circuits, allowing the system to maintain critical functions even when one power source fails. This segmentation resolves the contradiction by improving reliability through redundancy while keeping each power source module relatively simple.
Solution Approach 2:
The patent implements beforehand cushioning by providing a backup power source (second power source) that can take over when the primary power source (first power source) fails. The gate drive circuits are designed to switch between power sources, ensuring that the three-phase active short circuit function remains available even after power source failure, thus cushioning against the harmful effect of complete system failure.
2Reliability
If independent power sources and gate drive circuits are provided for each phase of inverter bridges, then system reliability is improved, but device complexity and costs increase
Solution Approach 1:
The control system is segmented into upper and lower bridge arm control units, each with independent gate drive circuits and power sources. This segmentation allows the system to maintain partial functionality even when parts of the system fail, improving reliability while keeping each segmented unit relatively simple and manageable.
Solution Approach 2:
The patent implements universality by designing the second power source (low-voltage battery) to serve multiple functions: it can power the lower bridge arm gate drive circuits under normal conditions, and it can also power the upper bridge arm gate drive circuits when the first power source fails. This multi-functionality improves reliability without proportionally increasing system complexity.
3Object-affected harmful factors
If a single-point power source is used, then the system architecture remains simple, but the system cannot prevent damage from motor energy backflow when the power source fails
Solution Approach 1:
The patent applies beforehand cushioning by pre-configuring a backup power source (second power source) that can immediately take over when the primary power source fails. This ensures that the gate drive unit can still execute protective functions (three-phase active short circuit) to prevent motor energy backflow damage, even after power source failure. The cushioning effect prevents the harmful consequence without requiring overly complex real-time response mechanisms.
Solution Approach 2:
The patent implements copying by creating a redundant power source system where the second power source replicates the functionality of the first power source. This copying approach ensures that critical protective functions can be maintained even when the original power source fails, preventing damage from motor energy backflow while keeping each copied module relatively simple.
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
Ensures reliable execution of three-phase active short circuits, preventing damage and unexpected braking torque by maintaining system functionality despite single-point power source failures, while reducing costs and maintaining a simple architecture.
Implementation Method 1
the first power source conversion unit uses a high-voltage bus buck conversion circuit
Implementation Method 2
the second power source conversion unit uses a low-voltage battery power source conversion circuit
Data Source
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AI summary
This application provides a motor control system and a vehicle, to reliably perform a three-phase active short circuit on a motor when a single-point power source fails. The motor control system includes a bus capacitor and a motor. The motor is connected to a positive direct current bus and a negative direct current bus through three phases of inverter bridges, the positive direct current bus and the negative direct current bus are respectively connected to a positive terminal and a negative terminal of the bus capacitor, and each phase of inverter bridge includes an upper bridge arm connected to the positive direct current bus and a lower bridge arm connected to the negative direct current bus. In addition, the motor control system further includes: an upper gate drive circuit, a lower gate drive circuit, a first power supply unit, and a second power supply unit. The first power supply unit is connected to three upper bridge arms in the three phases of inverter bridges through the upper gate drive circuit. The second power supply unit is connected to three lower bridge arms in the three phases of inverter bridges through the lower gate drive circuit.