HVDC Brushed Motor PWM Control for Paint Sprayer Thermal Management
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Solution Overview
Problem
High voltage direct current (HVDC) brushed motor controllers in paint sprayers experience thermal trips and reduced motor brush life due to high peak currents, leading to overheating and inefficient operation.
Innovation Solution
A high speed pulse width modulated (PWM) drive signal is used to control the HVDC motor, modulating the duty cycle to manage current flow and reduce peak and RMS currents, thereby preventing overheating and extending brush life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon controlled rectifiers (SCRs) or Triacs are used to control the HVDC motor, then the control design is simplistic and inexpensive, but high peak currents occur causing motor thermal trips and reduced brush life
Solution Approach 1:
The patent applies parameter changes by switching from traditional SCR/Triac control to PWM control, fundamentally changing the electrical parameters (current waveform, frequency, duty cycle) to eliminate peak currents while maintaining control functionality. This resolves the contradiction by improving reliability through parameter optimization without significantly increasing manufacturing complexity.
Solution Approach 2:
The patent implements periodic action through PWM control, where current is delivered in controlled pulses rather than continuous flow. By modulating the duty cycle of these periodic pulses, the system maintains motor operation while eliminating the harmful peak currents that cause thermal trips and brush wear, thus improving reliability.
2Ease of manufacture
If silicon controlled rectifiers (SCRs) or Triacs are used to control the HVDC motor, then the control design is simplistic and inexpensive, but motor thermal trips occur due to overheating
Solution Approach 1:
The patent changes the electrical control parameters from traditional phase-angle control to PWM control, which fundamentally alters how power is delivered to the motor. This parameter change enables precise control of average current and eliminates peak currents, thereby reducing motor temperature and preventing thermal trips while maintaining manufacturing simplicity.
Solution Approach 2:
The patent uses periodic PWM pulses to control motor operation, allowing the motor to rest between pulses and dissipate heat. This periodic action pattern prevents continuous overheating and thermal trips while maintaining effective motor control, resolving the temperature issue without complicating the control design.
3Power
If high peak currents are used to drive the motor, then the motor can drive the pump, but brush life is negatively affected
Solution Approach 1:
The patent applies parameter changes by transforming the current delivery method from high peak currents to controlled PWM pulses with optimized duty cycles. This maintains the necessary average power for pump operation while eliminating the high peak currents that cause brush erosion, thereby extending brush life without sacrificing motor power capability.
Solution Approach 2:
The patent implements periodic PWM control where current is delivered in controlled intervals rather than continuous high peaks. This periodic action maintains sufficient average power for pump operation while allowing brush wear to be minimized through reduced peak current exposure, resolving the contradiction between power delivery and brush life.
4Weight of moving object
If a smaller, lighter motor is used, then the sprayer weight is reduced, but the motor must still drive a three-piston pump efficiently
Solution Approach 1:
The patent applies parameter changes through PWM control, which optimizes the electrical parameters delivered to the motor. This enables smaller, lighter motors to achieve the necessary power output for driving the three-piston pump by improving electrical efficiency and eliminating power losses associated with traditional SCR/Triac control, thus reducing sprayer weight while maintaining power capability.
Solution Approach 2:
The patent uses periodic PWM control to deliver power efficiently to the motor, enabling smaller motors to achieve required power levels through optimized pulse delivery. This periodic action improves motor efficiency and allows weight reduction while maintaining the ability to drive the pump effectively.
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 effectively eliminates motor thermal trips, increases brush life, and enhances motor efficiency, allowing for a smaller, lighter motor capable of driving a three-piston pump with reduced power wastage and improved spray performance.
Implementation Method 1
The motor controller drives the motor with a high speed pulse width modulated (PWM) drive signal that switches current through the motor on and off
Data Source
AI summary
A fluid sprayer includes a housing, a pump, a nozzle, a high voltage direct current (HVDC) brushed electric motor that drives the pump, and a motor controller electrically connected to the motor. The motor controller drives the motor with a high speed pulse width modulated (PWM) drive signal that switches current through the motor on and off. The motor controller varies the PWM signal as a function of a spray setting input and sensed current through the motor.