Power Converter Control for Rotor-Stopped Battery Warming
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Solution Overview
Problem
Existing control apparatuses for electric power converters in vehicles fail to effectively generate sufficient heat during rotor-stopped states, leading to inefficiencies in battery warming and potential rotor movement due to unbalanced torque generation.
Innovation Solution
A control apparatus that calculates target d-axis and field currents to supply sinusoidal d-axis and q-axis currents to armature windings while adjusting the amplitudes of the field current to equalize heat generation across phases, using inductances and electrical angles to maintain rotor stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If d-axis current is supplied to armature windings while rotor is kept in rotation-stopped state, then battery can be warmed up, but the amount of heat generated is insufficient
Solution Approach 1:
The patent changes the control parameters by introducing q-axis current in addition to d-axis current, and by adjusting the field current amplitude dynamically. This transforms the single-parameter control (d-axis only) into multi-parameter control (d-axis + q-axis + field current), thereby increasing heat generation effectiveness while maintaining rotor stability.
Solution Approach 2:
The patent applies periodic switching control to the power converter switches, creating alternating current flow through the armature windings. This periodic action generates I²R heating effects in the battery while the alternating nature helps maintain rotor stability by averaging out torque fluctuations over complete cycles.
2Productivity
If q-axis current is supplied to increase heat generation, then battery warming efficiency improves, but rotor may move due to unbalanced torque
Solution Approach 1:
The patent uses field current as a counterbalancing mechanism to offset the destabilizing torque produced by q-axis current. By adjusting the field current amplitude and phase, the system creates opposing magnetic fields that cancel out the torque fluctuations, thereby maintaining rotor stability while allowing effective heat generation.
Solution Approach 2:
The control apparatus employs feedback mechanisms to monitor rotor position and adjust control parameters dynamically. By detecting rotor movement tendencies and adjusting d-axis, q-axis, and field currents accordingly, the system maintains stability while optimizing heat generation performance.
3Temperature
If field current amplitude is increased to enhance heat generation, then battery warming improves, but heat generation becomes unbalanced across phases
Solution Approach 1:
The patent dynamically adjusts the field current amplitude based on real-time conditions including rotor position, phase current balances, and temperature requirements. This dynamic adaptation allows the system to maintain balanced heat distribution across all phases while optimizing total heat generation effectiveness for battery warming.
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 ensures balanced heat generation across switches, preventing rotor movement and enhancing battery warming efficiency by equalizing phase currents, thus optimizing temperature raising control.
Implementation Method 1
a rotating electric machine having armature windings respectively of a plurality of phases and a field winding
Implementation Method 2
the temperature of the battery is raised with a rotor of the rotating electric machine kept in a rotation-stopped state
Data Source
Figure 1
Figure 2~3(C)
Figure 4
AI summary
A control apparatus (60) includes: a target value calculation unit configured to calculate a target field current to be supplied to a field winding (32) and target d-axis and target q-axis currents to be supplied to armature windings (34U to 34W); an armature control unit configured to perform switching control of upper-arm and lower-arm switches (SUH to SWL) for each phase, which are included in a first electric power converter (20), so as to control d-axis and q-axis currents flowing through the armature windings respectively to the calculated target d-axis and target q-axis currents; and a field control unit configured to perform switching control of a second electric power converter (40) so as to control field current flowing through the field winding to the calculated target field current. Moreover, the target value calculation unit is further configured to calculate the target d-axis current so as to satisfy both a requirement of making torque generated by a rotating electric machine (30) a torque with which a rotor can be kept in a rotation-stopped state and a requirement that the vector of the field current flowing through the field winding have a component that reduces reluctance torque of the rotating electric machine.