Multi-Stage Power Supply Circuit for High-Voltage DC Conversion
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Solution Overview
Problem
Existing power supply circuits for high-speed and high-torque permanent magnet motors face challenges in managing excessive voltage, leading to potential hardware failures and flux weakening, especially when the inverter DC bus voltage exceeds 1000V, due to bulky size, high cost, and thermal issues, which are exacerbated by the need for reinforced insulation and larger transformer sizes.
Innovation Solution
A modular, scalable power supply system with multiple stages connected in series, utilizing a first circuit block for start-up power, a second for PWM signal generation, a third for transistor control, a fourth for magnetic flux reset, and a fifth for voltage regulation, along with a power converter diagnosis system to ensure efficient and isolated low-voltage output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single-stage power supply is used to convert high-voltage DC to low-voltage DC, then the conversion can be achieved, but the transformer size becomes bulky and heat loss increases
Solution Approach 1:
The power supply is divided into multiple stages, each handling a portion of the voltage conversion. The first stage converts high-voltage DC to an intermediate voltage, and the second stage converts the intermediate voltage to low-voltage DC. This segmentation allows each transformer to be smaller than a single-stage transformer would be, reducing overall size and heat loss.
2Power
If the inverter DC bus voltage is raised above 1000V to increase power capability, then higher power output is achieved, but thermal issues and hardware failure risk increase
Solution Approach 1:
By segmenting the voltage conversion into multiple stages, each stage operates at lower voltage and power levels, generating less heat per stage. The distributed architecture allows heat to be spread across multiple components rather than concentrated in a single high-power transformer, improving thermal management.
Solution Approach 2:
The multi-stage conversion introduces intermediate voltage levels between the high-voltage DC bus and the low-voltage output. These intermediate stages act as mediators that step down the voltage progressively, reducing the stress on any single component and lowering overall thermal generation.
3Device complexity
If a single-stage power supply is used, then the circuit structure is simple, but the insulation requirements and transformer size increase excessively
Solution Approach 1:
The power conversion is segmented into multiple stages with intermediate voltage levels. Each stage has its own transformer and control circuitry, allowing the insulation requirements to be distributed across stages rather than requiring a single large transformer with excessive insulation. The modular structure maintains reasonable complexity while reducing transformer size.
4Power
If existing power supply designs are used for high-voltage DC conversion, then power conversion is achieved, but the system becomes bulky and expensive
Solution Approach 1:
The power supply is segmented into modular stages that can be manufactured and tested independently. This modularity reduces manufacturing complexity and cost compared to building a single large high-voltage system. The segmented approach allows for standardized components and easier assembly, reducing overall manufacturing cost despite the multiple stages.
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 modular power supply system effectively converts high-voltage DC to low-voltage DC, maintaining efficiency and reducing size and cost by minimizing transformer size and heat loss, while ensuring reliable operation even at high temperatures and high voltages, thus preventing hardware failures and flux weakening.
Implementation Method 1
a transformer to convert the high-voltage DC to a low-voltage DC
Implementation Method 2
a first capacitor connected in parallel to the resistor; a second capacitor connected in parallel to the transistor
Implementation Method 3
a first diode electrically connecting the resistor and the first capacitor; a second diode electrically connecting the second capacitor and the fifth circuit block
Data Source
Figure 1
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AI summary
A power supply circuit for converting a first voltage to a second voltage where the first voltage is greater than the second voltage, and a power train having the same, are provided. The power supply circuit may have multiple stages and each stage of the power supply circuit may include a first circuit block configured to provide a start-up power to a second circuit block; a second circuit block configured to generate a Pulse-Width-Modulation (PWM) signal that controls a pulse duration of a transistor; a third circuit block configured to activate or deactivate the transistor based on the PWM signal; a fourth circuit block configured to reset a magnetic flux in a transformer to a zero state when the transistor is deactivated; and a fifth circuit block configured to maintain an output of a stage below a predetermined value by adjusting a voltage across the transformer.