Air Conditioner FOC Solution

Application

Description

Complete sensorless FOC solution for air conditioner compressor motors using LKS07 high-performance MCU. Includes field weakening for wide speed range and MTPA for maximum efficiency.

Core Advantages

High Efficiency MTPA and optimized FOC achieve >95% efficiency, reducing energy consumption
Wide Speed Range Field weakening extends speed range to 150% of base speed for variable capacity
Reliable Start Specialized start-up algorithm ensures reliable start under compressor load
Low Noise Vibration suppression and smooth torque control minimize acoustic noise

Recommended Bill of Materials (BOM)

Item Part Number Description Quantity Datasheet
1 LKS32MC037M6S8 Motor control MCU with DSP 1 📄 Download
2 LKS_GD_6N_1A5 6N gate driver 1 📄 Download
3 IPB017N10N5 100V MOSFET 6 📄 Download
4 LKS_PMIC_5V_500 5V LDO for MCU 1 📄 Download

Applications

Residential air conditioners
Commercial HVAC systems
Heat pump compressors
Refrigeration compressors

Technical Specifications

Topology
Three-phase inverter
Current Sensing
Single shunt reconstruction
P W M Frequency
10kHz
Control Loop
50us current, 1ms speed
Position Estimation
Sliding mode observer
Start-up Method
I-f start with transition
Protection
OCP, OVP, OTP, stall detection

Customer Success Stories

HVAC Manufacturer

Home Appliances | Variable Speed Air Conditioner

Challenge

Develop high-efficiency variable speed compressor drive for residential air conditioner requiring >95% efficiency, wide speed range, and reliable start under pressure.

Solution

Implemented sensorless FOC using LKS32MC037 with MTPA and field weakening. Used single-shunt current sensing for cost optimization. Customized start-up algorithm for compressor load.

Results

Achieved 96.5% peak efficiency. Speed range 1000-9000 RPM provides 9:1 capacity variation. Reliable start-up in 500ms under 2.5MPa pressure. Passed 10,000 cycle reliability test.

FAE Expert Insights

D

David Wang

Senior FAE - Motor Control Systems

18 years

Professional Insights

[Data Pending] FAE insights to be added based on actual application experience with this solution.

Key Takeaways

  • Use LKS07/LKS08 with dedicated DSP for FOC
  • Single-shunt sensing adequate with proper algorithm
  • Specialized start-up essential for compressor
  • Tune observer for specific motor parameters

Decision Framework

Decision Framework
Steps:
  1. Evaluate requirements
  2. Compare solutions
  3. Consult FAE

Ready to Implement This Solution?

Contact our FAE team for design support and quotes

Contact Us Now

Frequently Asked Questions

Why is sensorless FOC challenging for compressor applications?

Compressor sensorless FOC challenges: (1) Low speed operation - at low speeds, back-EMF is too small for reliable position estimation

(2) High load start - pressure differential creates high starting torque requirement

(3) Parameter variation - motor temperature affects resistance and inductance

(4) Vibration - compressor mechanical vibration affects electrical measurements

(5) Speed range - wide speed range requires different control strategies. Solutions: (1) I-f start - open-loop current forcing at start-up until sufficient speed for observer

(2) Robust observer - sliding mode or flux observer tolerant to parameter variation

(3) Temperature compensation - adjust parameters based on temperature

(4) Mechanical filtering - electrical filtering to separate mechanical vibration from electrical signals.

Use I-f start for low speed. Implement robust observer. Add temperature compensation.

How does MTPA improve efficiency in compressor applications?

MTPA (Maximum Torque Per Ampere) optimization: (1) Principle - for IPM motors, torque has two components: electromagnetic (Iq) and reluctance (Id). MTPA finds optimal Id/Iq ratio for maximum torque per ampere

(2) Efficiency gain - typically 5-15% efficiency improvement at partial loads

(3) Implementation - lookup table or analytical calculation based on motor parameters

(4) Operating points - most beneficial at light and medium loads where compressor spends most time

(5) Energy savings - significant energy savings over compressor lifetime. For air conditioners, MTPA is essential for meeting energy efficiency regulations. The efficiency improvement is most noticeable at part-load conditions where the compressor operates most of the time.

Implement MTPA for IPM motors. Use lookup table for real-time efficiency optimization.