Rotary Electric Machine Control Phase Synchronization
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Solution Overview
Problem
When switching from PWM control to torque-feedback control in rotary electric machines, existing systems experience a decrease in torque responsivity due to the need to interrupt feedback control and obtain phase-specific current measurements, leading to reduced responsiveness to torque commands.
Innovation Solution
An apparatus that includes a switching control unit to sample output currents at predetermined phases during PWM control, allowing these values to be used for seamless transition to torque-feedback control, thereby maintaining torque responsivity by synchronizing current sampling phases between control routines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the control apparatus switches from PWM control routine to torque-feedback control routine by obtaining measured values of output currents at predetermined phases, then the inverter voltage utilization factor is improved, but the torque responsivity deteriorates due to interruption of feedback control
Solution Approach 1:
The patent applies preliminary action by having the second control unit sample output currents at predetermined phases during the PWM control routine execution. This preliminary sampling prepares the necessary current data in advance, so when switching to torque-feedback control routine, the control can immediately use these pre-sampled values without interrupting the feedback control flow, thus maintaining torque responsivity while enabling voltage utilization improvement
Solution Approach 2:
The patent maintains continuity of useful action by ensuring that the feedback control operation continues without interruption during the switching process. The first control unit continues PWM control while the second control unit simultaneously samples current values, and the sampled values are seamlessly transferred to the torque-feedback control routine, eliminating any gap in the control action that would otherwise reduce torque responsivity
Data Source
AI summary
In an apparatus, a first control unit performs current-feedback control, and a second control unit performs torque-feedback control. The torque-feedback control samples values of each output current at phases. The sampled values of each output current at the phases are referred to as phase-related sampled values of the corresponding output current. The apparatus causes the second control unit to sample values of each output current at the predetermined phases while the first control unit is performing the current-feedback control when switching the current-feedback control to the torque-feedback control. The second control unit uses the values of each output current sampled by the first control unit as the phase-related sampled values of the corresponding output current to start the torque-feedback control when the current-feedback control is switched to the torque-feedback control.