logo-mobile

ROHM

ROHM
Menu
  • Arduino –
  • Raspberry Pi –
  • Trending –
  • Others –
  • About –
  • Contact –

Glossary

How To Calculate Power Consumption

Device Plus Editorial Team
Published by Device Plus Editorial Team at June 25, 2016
Categories
  • Glossary
  • Others
Tags
  • motor
how to calculate power consumption

Figure 1. Equivalent Circuit Example

Question: Is the power consumption of brush motor drivers calculated by:
(LSI Circuit Current x Motor Current) x Supply Voltage?

 

Answer: With the (Motor Current x Supply Voltage) calculation, since the power  consumption of the motor itself is included, determining the driver power consumption Pc when operating at a constant voltage becomes basically:

Pc = (Small-Signal Circuit Current x Source Voltage) + [Motor Current x (Low-Side Output Voltage + High-Side Output Voltage)].

how to calculate power consumption

Figure 1. Equivalent Circuit Example

In the equivalent circuit in Fig. 1 above we have a Small Signal Circuit Current Icc, Supply Voltage Vcc, and Motor Current Io. Since the MOS output is often represented by resistance values, given an ON resistance at the high-side output RonH and a low-side ON resistance of RonL, the High Side Output Voltage VH is determined by Io x RonH and, similarly, the Low Side Output Voltage VL by Io x RonL. This makes it possible to calculate the power consumption Pc by: Icc x Vcc + Io x (VH + VL) → Icc x Vcc + Io2 x (RonH + RonL).

How To Calculate Power Consumption During PWM Drive

how to calculate power consumption

Figure 2. PWM Operation

As an example, during current regeneration operation with the 2 outputs leading to the motor, consider the case of ON operation of the output transistor at the ground side as in Figure 2b above.

In one period of PWM operation (tpwm), at output OUT1 we define:

tr: Time to transition from Low to High

tdr: Current supply time to maintain High

tf: Time to transition from High to Low

trc: The time for current regeneration in order to maintain Low, which is divided into 4 parts; the other output OUT2 is in continuous Low operation.

An easy way to think of this operation and how to calculate power consumption is that the voltage change from output high to low and vice versa are constant and in a straight line between currents. The current change during regeneration and voltage supply is also in a straight line.

how to calculate power consumption

The energy consumption of the voltage change component is the product of the voltage time constant and current time constant integrated at each time, while the power consumption of the current change component is determined by the product of the resistance and square of the current time constant, integrated at each time.

The energy consumption Er of the tr component is:

Er ≒ • ip1 • VM・tr + (ip1)2 • RonL • tr

The energy consumption Ef of the tf component is:

Ef ≒ • ip2 • VM • tf + (ip2)2 • RonL • tf

The energy consumption Edr of the tdr component is:

Edr ≒ • {(ip1)2 + ip1 • ip2 + (ip2)2} • (RonH + RonL) • tdr

The energy consumption Erc of the trc component is:

Erc ≒ • {(ip1)2 + ip1 • ip2 + (ip2)2} • (2 • RonL) • trc

The output power consumption Pc_ot is calculated from the sum of these 4 components divided by the total time:

Pc_ot ≒ (Er + Edr + Ef + Erc)/tpwm

To arrive at the total power consumption Pc we need to add the circuit current Icc and supply voltage Vcc:

Pc ≒ Pc_ot + Vcc • Icc

In the case that tr and tf are sufficiently smaller than tpwm with virtually no current change and ip1=ip2, the power is determined by:

Pc ≒ (ip1)2 • {(RonH + RonL) • tdr/tpwm + (2 • RonL) • trc/tpwm} + Vcc • Icc

which is the sum of the ratios of the drive time and regenerative time with respect to a single PWM period of generated power based on the changed current pathway during drive operation.

Device Plus Editorial Team
Device Plus Editorial Team
Device Plus is for everyone who loves electronics and mechatronics.

Check us out on Social Media

  • Facebook
  • Twitter

Recommended Posts

  • Simple DC Brush Motor ControlSimple DC Brush Motor Control
  • Power Consumption During Current Regeneration FlowPower Consumption During Current Regeneration Flow
  • Motor Current When Applying a Torque LoadMotor Current When Applying a Torque Load
  • Maximum Current Flow to MotorMaximum Current Flow to Motor
  • Maximum Rated Output CurrentMaximum Rated Output Current
  • How To Make Parking Assist Car SensorsHow To Make Parking Assist Car Sensors
Receive update on new postsPrivacy Policy

Recommended Tutorials

  • How to integrate an RFID module with Raspberry Pi How to integrate an RFID module with Raspberry Pi
  • How to Use the NRF24l01+ Module with Arduino How to Use the NRF24l01+ Module with Arduino
  • How to Run Arduino Sketches on Raspberry Pi How to Run Arduino Sketches on Raspberry Pi
  • Setting Up Raspberry Pi as a Home Media Server Setting Up Raspberry Pi as a Home Media Server

Recommended Trends

  • SewBot Is Revolutionizing the Clothing Manufacturing Industry SewBot Is Revolutionizing the Clothing Manufacturing Industry
  • All About The Sumo Robot Competition And Technology All About The Sumo Robot Competition And Technology
  • 5 Interesting Tips to Calculating the Forward Kinematics of a Robot 5 Interesting Tips to Calculating the Forward Kinematics of a Robot
  • Go Inside the Drones That Are Changing Food Delivery Go Inside the Drones That Are Changing Food Delivery
Menu
  • Arduino –
    Arduino Beginner’s Guide
  • Raspberry Pi –
    Raspberry Pi Beginner's Guide
  • Trending –
    Updates on New Technologies
  • Others –
    Interviews / Events / Others

Check us out on Social Media

  • Facebook
  • Twitter
  • About
  • Company
  • Privacy Policy
  • Terms of Service
  • Contact
  • Japanese
  • 简体中文
  • 繁體中文
Don’t Forget to Follow Us!
© Copyright 2016-2023. Device Plus - Powered by ROHM
© 2023 Device Plus. All Rights Reserved. Muffin group

istanbul escort istanbul escort istanbul escort