Synchronous motor driving device, blower, and air conditioning device
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Solution Overview
Problem
Parallel drive systems for brushless synchronous motors face instability issues, particularly at low speed rotation, leading to pulsating current and speed instability, which restricts the drive range and increases costs due to the need for multiple power sources.
Innovation Solution
A synchronous motor drive device that selectively connects stably drivable motors in parallel to a power converter, allowing optional motors to be driven at various speeds, thereby stabilizing operation and reducing the number of motors needed to be driven at low speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple brushless synchronous motors are connected in parallel to one power source, then the number of power sources is reduced and cost is suppressed, but the system becomes unstable at low speed rotation with pulsating current
Solution Approach 1:
The patent applies dynamics by making the drive system adaptable through selective motor activation. The controller dynamically determines which motors to drive based on load requirements, and the switch devices enable dynamic reconfiguration of the parallel-connected motors. This allows the system to operate stably by activating only the necessary number of motors rather than running all motors in parallel, thereby resolving the instability issue while maintaining cost benefits.
2Speed
If all parallel-connected motors are driven at low speed, then the drive system can operate at low speeds, but hunting occurs and current pulsation increases
Solution Approach 1:
The patent applies partial action by activating only the necessary number of motors based on load requirements rather than driving all motors simultaneously. The controller calculates the required number of motors based on the relationship between load torque and motor count, and selectively activates that many motors using the switch devices. This partial activation approach maintains stable operation at low speeds by avoiding the hunting and current pulsation that occurs when all motors are driven.
3Object-generated harmful factors
If brushless synchronous motors are used instead of induction motors, then contactless operation is achieved, but the cost of the power source increases when multiple motors are driven
Solution Approach 1:
The patent applies universality by designing a single power source with an inverter device that can drive multiple brushless synchronous motors. The inverter device is configured to output multiple sets of phase signals, allowing one power source to perform the function of multiple separate power sources. Combined with selective motor activation based on load requirements, this universal power source approach maintains contactless operation benefits while reducing the total number of power sources needed.
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 enables stable operation of multiple brushless synchronous motors by selectively driving only necessary motors at optimal speeds, reducing instability, noise, and loss, while minimizing component costs and maintaining performance.
Implementation Method 1
a power converter 1, a controller 30... the power converter 1... supply power to a plurality of motors M1, M2 to Mn
Data Source
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AI summary
A synchronous motor drive device is a synchronous motor drive device that drives a plurality of synchronous motors connected in parallel to one another, and includes a power converter that converts power from a power source to supply the power to the plurality of synchronous motors, a first switch device that electrically connects or disconnects between the power converter and each of the plurality of synchronous motors, and a controller that, based on a higher order command, performs stability judgment processing of the plurality of synchronous motors, determines the number of synchronous motors to be driven and a drive speed from among the plurality of synchronous motors, selects a synchronous motor corresponding to the number of the synchronous motors from among the plurality of synchronous motors, controls the first switch device corresponding to the selected synchronous motor to electrically connect the power converter to the synchronous motor and to supply the power, and instructs, to the power converter, the drive speed of the synchronous motor to be driven.