Motor Driver Circuit with Shared Inductor for Bidirectional Control
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Solution Overview
Problem
Conventional electrical motors with multiple phases are expensive due to costly phase driver electronics, and they operate inefficiently at reduced power levels due to less effective magnetic field coupling, requiring mechanical gearboxes and complex transmission systems to maintain efficiency across a wider range of output levels.
Innovation Solution
A driver circuit configuration that includes a boost converter and a buck converter, where the inductive element is provided by the coil winding and the charge storage element is referenced to a supply node, allowing for bidirectional operation and reducing the size and cost of the charge storage element by bypassing the electrical supply during charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional PWM voltage controllers with H-bridge topology are used to drive motor coils, then the motor can operate with bidirectional control, but the cost of driver circuitry increases significantly due to large power supply requirements and high voltage/current components
Solution Approach 1:
The patent combines the boost converter and buck converter into a single integrated driver circuit that shares common components (inductor, switches, diodes, capacitor) between the two conversion modes. This merging eliminates the need for separate driver circuits for each direction, reducing component count and cost while maintaining bidirectional control capability.
Solution Approach 2:
The driver circuit is designed to perform multiple functions using the same hardware infrastructure. The same inductor, switches, and capacitor serve both the boost conversion function (for one direction) and the buck conversion function (for the other direction), making the circuit universal and eliminating the need for dedicated components for each operation mode.
2Adaptability or versatility
If variable output driver circuits are provided to allow motor operation at reduced output power levels, then the motor can operate at lower power, but the motor efficiency is markedly reduced due to less effective coupling of smaller magnetic fields
Solution Approach 1:
The patent changes the operating parameters of the motor by using bidirectional current flow through the coils, which creates stronger magnetic field coupling. The boost and buck conversion modes enable the motor to operate efficiently at reduced power levels by optimizing the magnetic field interaction, thereby maintaining efficiency across a wider range of output levels without requiring mechanical gearboxes.
3Ease of operation
If the charge storage element is referenced to ground node, then the circuit operation is simplified, but the size and cost of the charge storage element increases
Solution Approach 1:
The patent references the charge storage element (capacitor) to the supply node instead of the ground node, representing a dimensional shift in the circuit reference architecture. This change allows the capacitor to operate with smaller voltage swings and store the necessary energy with reduced capacitance value, thereby decreasing its size and cost while maintaining proper circuit operation through the bidirectional boost and buck conversion process.
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
This configuration reduces the overall cost of the driver circuit, enables efficient operation at reduced power levels, and eliminates the need for mechanical gearboxes by recycling energy, allowing the motor to operate efficiently across a wide range of output levels.
Implementation Method 1
an inductive element of the boost converter and the buck converter is provided by said coil winding of the at least one of the plurality of stator teeth
Implementation Method 2
a boost converter comprising a charge storage element and coupled to a first terminal of a coil winding on at least one of the plurality of stator teeth; and a buck convener comprising said charge storage element
Data Source
AI summary
Apparatus is provided comprising an electrical motor comprising a rotor and a stator, the rotor comprising a plurality of rotor teeth and the stator comprising a plurality of stator teeth. The apparatus has a driver circuit to drive the electrical motor comprising a boost converter comprising a charge storage element and coupled to a first terminal of a coil winding on at least one of the plurality of stator teeth, and a buck converter comprising the same charge storage element and coupled to the same first terminal of the coil winding on the at least one of the plurality of stator teeth. An inductive element of the boost converter and the buck converter is provided by the coil winding of the at least one of the plurality of stator teeth, and the charge storage element is referenced to a supply node for coupling the second terminal of the coil winding to an electrical supply.