Power Converter Controller Mode Switching for Inverter Size Reduction
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Solution Overview
Problem
Existing power converting systems face challenges in reducing the size of inverters and minimizing current draw from batteries when controlling rotary electric machines with multiple sets of three-phase windings, particularly at zero rotational speed, leading to increased size and potential voltage drops.
Innovation Solution
A power converting device with a controller that determines combination patterns for energization durations of multiple sets of one-phase windings, adjusting impedance to control input current levels and improve controllability, using a switch connected between the power source and windings to manage drive pulse signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PWM control is applied to the inverter, then controllability for input current is improved, but the inverter size increases due to the need for high-capacitance capacitor
Solution Approach 1:
The patent dynamically switches between PWM control mode and pulse control mode based on the rotational speed of the rotor. When rotational speed is above a predetermined threshold, PWM control is used for high controllability. When rotational speed is zero or below the threshold, pulse control is used to reduce capacitor requirements and inverter size. This dynamic adaptation resolves the contradiction by optimizing the control mode according to operating conditions.
2Volume of moving object
If pulse control is applied to the inverter, then inverter size is reduced, but controllability for input current deteriorates causing high current draw from battery
Solution Approach 1:
The patent changes the control parameter (control mode) based on the rotational speed parameter. By monitoring rotational speed and switching between PWM and pulse control modes, the system optimizes the balance between inverter size and input current controllability. This parameter-based adaptation allows the system to achieve compact size while maintaining acceptable controllability within specific operating ranges.
3Volume of moving object
If pulse control is used with zero rotational speed, then inverter size is reduced, but battery voltage drops due to high current draw
Solution Approach 1:
The patent implements dynamic mode switching that prevents pulse control from being used when rotational speed is zero or below a predetermined threshold. By requiring PWM control mode under these conditions, the system ensures adequate input current controllability and prevents excessive battery current draw, thereby maintaining battery voltage stability and system reliability while still allowing size reduction during appropriate operating conditions.
4Power
If thicker wires are used to handle high current, then current carrying capacity is improved, but weight and wiring complexity increase
Solution Approach 1:
The patent changes the control mode parameter to pulse control under specific conditions (positive rotational speed above threshold), which reduces input current ripple and allows the use of thinner wires with lower current carrying capacity requirements. This parameter-based optimization reduces wire weight and wiring complexity while maintaining adequate power transmission capability for the given operating conditions.
Data Source
AI summary
In a power converting device, a controller determines a combination pattern of a first energization pattern for the first set of the at least one-phase winding and a second energization pattern for the second set of the at least one-phase winding. The first and second energization patterns respectively include at least a first energization duration for the first set of the at least one-phase winding and a second energization duration for the second set of the at least one-phase winding. The controller supplies a drive pulse signal, whose on duration is based on the determined combination pattern, to the switch to thereby control on-off operations of the switch.