Motor Relay Drive Using a Shared Charge Pump Pre-Driver
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional motor driver circuits struggle to handle high voltage auxiliary battery systems in electric vehicles, requiring dedicated driver circuits for motor relays, which complicates downsizing and integration.
Innovation Solution
A motor driver configuration that includes an inverter, a multiphase pre-driver circuit, and semiconductor motor relays, where the pre-driver circuit uses a charge pump to boost battery voltage, allowing the motor relays to be driven without a dedicated driver circuit, enabling operation with voltages up to 24 volts or 48 volts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated driver circuit is used for motor relays in high voltage systems, then the motor relays can be reliably driven at high voltages (24V or 48V), but the device complexity and size increase
Solution Approach 1:
The pre-driver circuit is designed to perform multiple functions: it drives both the inverter switching elements and the motor relays using a single circuit architecture. The charge pump generates a boosted voltage that is distributed to both the high-side switching elements of the inverter and the motor relays, eliminating the need for separate driver circuits for each component.
Solution Approach 2:
The patent combines the motor relay driver function with the inverter pre-driver circuit into a single integrated unit. By merging these previously separate functions into one circuit, the overall system complexity is reduced while maintaining the ability to drive both components reliably at high voltages.
2Reliability
If a dedicated driver circuit is implemented for motor relays, then high voltage operation is achieved, but the overall system size increases
Solution Approach 1:
The pre-driver circuit serves dual purposes by driving both the inverter switching elements and the motor relays. This multi-functional design eliminates the need for additional dedicated driver circuitry, thereby reducing the overall system volume while maintaining high voltage operation capability.
Solution Approach 2:
By integrating the motor relay driver functionality into the existing pre-driver circuit, the patent reduces the total component count and system size. The charge pump and associated control logic are shared between driving the inverter and the motor relays, resulting in a more compact overall design.
3Reliability
If multiple separate driver circuits are used for inverter and motor relays, then each component can be optimized, but the integration and downsizing become difficult
Solution Approach 1:
The pre-driver circuit is designed as a universal driver that can drive different types of loads (inverter switching elements and motor relays) using the same basic architecture and voltage generation mechanism. This allows for optimized component design while maintaining ease of integration and potential for downsizing.
Solution Approach 2:
The patent merges previously separate driver circuits into a single integrated unit, making the system easier to manufacture and integrate. The unified design reduces the number of separate components that need to be managed during assembly and testing, while still allowing each driven component (inverter and motor relays) to be optimized for its specific function.
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 simplifies the motor relay drive and allows operation at higher voltages without a dedicated driver circuit, reducing size and cost while maintaining efficient motor control.
Implementation Method 1
The multiphase pre-driver circuit includes a charge pump that boosts a voltage of the battery. An output end of the charge pump is connected to the gate of the motor relay provided for each phase of the motor.
Data Source
AI summary
A motor driver includes an inverter, a multiphase pre-driver circuit, a controller and motor relays. The inverter includes pairs of an upper-arm switching element and a lower-arm switching element being connected in series between a ground line and a power supply line, and supplies power to a multiphase motor by converting direct current power of a battery. The multiphase pre-driver circuit drives the upper-arm and lower-arm switching elements. The controller commands the multiphase pre-driver circuit to drive the switching elements, and controls electrical conduction from the inverter to the multiphase motor. The motor relays interrupt a current flowing from the multiphase motor to the inverter during an off state. The multiphase pre-driver circuit includes a charge pump. The motor relays are turned on by an output voltage of the charge pump during an operation of the charge pump in a situation apart from that the controller provides an instruction.