I. Clarify Monitoring Objects: List of Core Inverter Raw Materials (Priority Categories for Control)

II. Real-Time Monitoring Solutions by Raw Material Type (Technical Methods + Implementation Steps)

1. Power Semiconductors (IGBTs/Rectifier Bridges): Focus on “Soldering Quality + Temperature Rise Stability”

• Monitoring Technologies: Reflow oven temperature profile monitors (e.g., KIC RPI), online In-Circuit Test (ICT) equipment, infrared thermal imagers (e.g., FLIR E54).
• Real-Time Monitoring Steps:
  1. Reflow Soldering Stage (After Mounting): Embed 6–8 temperature sensors in the reflow oven to collect the temperature profile of the IGBT pin soldering area in real time. The standard profile is: preheating zone at 150–180°C for 60 seconds, reflow zone at 230–250°C for 30 seconds. If the actual temperature deviates by more than ±5°C, the oven stops automatically and displays a “temperature abnormality” alarm on the screen.
  2. Assembly Stage (After Fixing Heat Sinks): Use online ICT equipment to test the contact resistance between IGBT pins and the PCB (standard value < 5mΩ). Test data is uploaded to the MES system in real time. If the resistance exceeds 10mΩ, the equipment locks, and workers need to inspect solder joints manually (e.g., check for solder balls or cold joints).
  3. Aging Test Stage (Preliminary Finished Product Testing): Use an infrared thermal imager to capture the surface temperature of the IGBT module in real time. Run the module at 80% of the rated load (e.g., with rated current input) for 30 minutes. If the local temperature rise exceeds 60K (surface temperature > 85°C at an ambient temperature of 25°C), it is judged as “poor heat dissipation”. Check the heat sink fitting gap (required to be < 0.1mm) or the amount of thermal grease applied (standard thickness: 0.1–0.2mm).

2. Capacitors (Bus Capacitors/Filter Capacitors): Focus on “Capacitance Drift + Leakage Current”

• Monitoring Technologies: Online LCR meters (e.g., Agilent E4980A), leakage current testers (e.g., Tonghui TH2689), high-temperature aging chambers (with real-time data collection).
• Real-Time Monitoring Steps:
  1. Preliminary Test After Insertion: After capacitors are soldered to the PCB, use an online LCR meter to measure capacitance in real time (e.g., for a 470μF/450V bus capacitor, the standard capacitance deviation is ±10%). The equipment locates the capacitor position automatically, and data is synchronized to the system. Capacitors with excessive deviation are marked as “unqualified” and sent to the rework area.
  2. High-Temperature Aging Stage: Place semi-finished inverters in a 60°C high-temperature aging chamber and operate them at the rated voltage for 2 hours. Use a leakage current tester to collect capacitor leakage current in real time (standard value < 1mA). If the leakage current exceeds 2mA continuously, the aging chamber powers off automatically and alarms for “abnormal capacitor leakage current,” requiring capacitor replacement.
  3. Finished Product Testing Stage: Use an oscilloscope to observe DC bus voltage ripple in real time (standard value < 5% of the rated voltage). Excessive ripple is usually caused by insufficient capacitance of filter capacitors. Trace back to LCR test data to check for hidden defects such as “qualified initial test but capacitance attenuation after aging”.

3. PCB Boards (Main Control/Power Boards): Focus on “Conductivity + Insulation”

• Monitoring Technologies: AOI (Automatic Optical Inspection) equipment (e.g., Test Research TR7007), flying probe testers (e.g., Tektronix TDX3000), insulation resistance testers (e.g., Hioki 3455).
• Real-Time Monitoring Steps:
  1. Post-Etching Inspection: After PCB etching, the AOI equipment scans the circuit pattern in real time through optical lenses to identify “circuit gaps (width < 80% of the design value) and short circuits (distance between adjacent circuits < 0.2mm)” automatically. If the defect rate exceeds 0.5%, stop operations to adjust etching parameters (e.g., etchant concentration, temperature).
  2. Conductivity Test Before Insertion: Use a flying probe tester to test the conductivity of PCB vias and circuits. Measure circuit resistance (standard value < 1Ω) and via impedance (standard value < 5Ω) in real time. Generate a test report linked to the “unique PCB code” for traceability in subsequent stages.
  3. Insulation Test After Soldering: After soldering the power PCB, use an insulation resistance tester to measure the “insulation resistance between high-voltage and low-voltage circuits” in real time (standard value > 100MΩ/500V). If the insulation resistance is < 50MΩ, it is judged as “solder mask damage,” requiring manual inspection of the circuit surface (e.g., check for residual solder causing short circuits).

4. Magnetic Components (Inductors/Transformers): Focus on “Inductance + Temperature Rise”

• Monitoring Technologies: Online inductance meters (e.g., GWINSTEK LCR-819), winding DC resistance testers (e.g., Changzhou Tonghui TH2512), temperature rise testers (e.g., Shanghai Acrel ARTU-K32).
• Real-Time Monitoring Steps:
  1. Winding Stage: During inductor coil winding, the equipment records the number of turns in real time (e.g., 100 turns for a common-mode inductor, allowed deviation ≤ 2 turns). Stop operations automatically if the number of turns is abnormal. Simultaneously, use a winding DC resistance tester to measure coil resistance (standard deviation ±5% of the design value). Excessive resistance may result from insufficient wire diameter or loose winding.
  2. After Dipping and Curing: Use an online inductance meter to measure inductance (e.g., 2mH for a differential-mode inductor, standard deviation ±10%). Excessive inductance deviation requires checking the magnetic core material (e.g., whether low-permeability magnetic cores are mixed) or winding density.
  3. Temperature Rise Test After Assembly: Connect the inductor to a test circuit and operate it at the rated current for 1 hour. Use a temperature rise tester to collect coil temperature in real time (standard temperature rise ≤ 40K). Excessive temperature rise requires investigating magnetic core loss (e.g., whether inferior magnetic cores are used) or insufficient heat dissipation space.

III. Build a Real-Time Monitoring Support System (Ensure Data Closure and Abnormality Traceability)

1. Data Collection and Analysis System (Core Support)

• Hardware Connection: Connect all online testing equipment (AOI, LCR meters, thermal imagers) to the MES system via industrial Ethernet (Profinet/Modbus-TCP). Set the data sampling interval to 1–5 seconds (≤1 second for key parameters such as soldering temperature and capacitor leakage current).
• Data Visualization: Build a “raw material quality monitoring dashboard” in the MES system, categorized by raw material type to display:
  • Real-time data: e.g., “Current IGBT soldering temperature: 235°C (normal), capacitor capacitance: 465μF (normal)”;
  • Abnormality statistics: e.g., “Today’s PCB AOI defect rate: 0.3% (below the 0.5% threshold), 3 IGBT soldering abnormalities (2 reworked)”.
• Trend Early Warning: The system automatically analyzes 7-day data trends (e.g., “Capacitor leakage current defect rate increased from 0.2% to 0.8%”) and sends early warnings to the procurement department to investigate potential batch-related raw material issues (e.g., quality fluctuations in capacitors from the same batch).

2. Abnormality Response Mechanism (Rapid Handling)

• Hierarchical Response:
  • Minor abnormalities (e.g., excessive capacitance of a single capacitor): The system marks the item automatically and sends it to the rework area, where on-site quality inspectors handle it within 1 hour.
  • Moderate abnormalities (e.g., 1.2% via defect rate in a batch of PCBs): Stop the production line, and quality engineers arrive to investigate within 30 minutes while notifying the supplier.
  • Severe abnormalities (e.g., continuous IGBT soldering temperature exceeding 260°C): Pause all related production lines in the factory. The technical team leads the analysis (e.g., reflow oven failure, IGBT pin oxidation) and issues a temporary solution within 2 hours.
• Closed-Loop Recording: Record all abnormality handling processes (causes, measures, results) in the system, linked to “raw material batch numbers + equipment IDs” for subsequent review.

3. Full-Process Traceability Mechanism (Responsibility Localization)

• One Item, One Code: Assign a unique “batch code” to each batch of raw materials (e.g., IGBT modules, PCBs). Scan and record the code in the system during processing to form a traceability chain: “raw material batch code → semi-finished product code → finished product serial number”.
• Problem Tracing: If a finished inverter experiences “IGBT overheating failure” at the customer site, traceability via the finished product serial number can identify:
  • Raw material information (IGBT batch number, supplier, incoming inspection report);
  • Production process data (soldering temperature profile, aging test temperature rise record);
  • Testing personnel (AOI operator, ICT tester), quickly determining whether the issue stems from “raw material defects” or “processing errors”.

• Develop a Supplier Access Standard and clarify mandatory requirements:

• • Qualification verification: Suppliers must provide production licenses, industry certifications (e.g., SC certification for food raw materials, RoHS certification for electronic components), and quality inspection reports from the past 3 years;

• • Production capacity and stability: Assess production scale (to ensure it matches the enterprise’s needs), equipment accuracy (e.g., calibration records for reactors used in chemical raw material production), and historical delivery performance (no more than 2 stock-outs or delays in the past year);

• • Quality control capabilities: Require suppliers to share their internal raw material inspection processes (e.g., whether they have an Incoming Quality Control (IQC) process) and abnormality handling mechanisms (e.g., return and exchange procedures for unqualified raw materials).

• On-site inspections: Conduct on-site visits to suppliers of core raw materials (e.g., key chemical additives that affect product performance, electronic components). Verify whether their production environment (e.g., clean room standards for food raw material factories) and testing equipment (e.g., availability of gas chromatographs, spectrometers, and other precision instruments) meet requirements.

• Classify suppliers into three levels—Grade A (core), Grade B (qualified), and Grade C (alternative)—based on “quality stability, delivery rate, and service response speed”:

• • Grade A suppliers: Account for no more than 30% of total suppliers. Offer priority procurement (allocate ≥60% of total orders) and preferential payment terms (e.g., extend payment cycles from 30 days to 45 days);

• • Grade B suppliers: Account for 60% of total suppliers. Serve as regular procurement partners and conduct monthly quality data evaluations;

• • Grade C suppliers: Account for ≤10% of total suppliers. Used only as backups. If a Grade B supplier’s pass rate falls below 98% for 3 consecutive months, demote them to Grade C and require rectification.

• Update supplier quality ledgers monthly: Record the inspection pass rate and number of abnormalities for each batch of raw materials. Track and urge rectification for underperforming suppliers.

• Create an Incoming Inspection Specification (SOP) for each type of raw material, specifying “inspection items, qualified ranges, testing methods, and judgment rules”:

• • Example 1 (Metal raw materials): Inspection items include “component content (e.g., Cr content ≥18% for stainless steel), dimensional tolerance (e.g., thickness deviation ≤±0.02mm), and surface defects (no scratches or rust spots)”. Testing methods include “using spectrometers for component analysis, micrometers for dimensional measurement, and visual inspection for surface defects”;

• • Example 2 (Food raw materials): Inspection items include “sensory indicators (normal color and odor), physical and chemical indicators (moisture content ≤15%), and microbial indicators (total bacterial count ≤1000 CFU/g)”. Testing methods refer to national GB standards.

• Share these standards with suppliers to avoid disputes caused by “inconsistent understanding of qualified standards between the supply and demand sides”.

• Sampling rules: Refer to GB/T 2828.1 (Sampling Procedures for Inspection by Attributes) and determine sampling ratios based on batch size (e.g., sample 5 pieces for batches of ≤100 pieces, 10 pieces for batches of 100–500 pieces). Focus on “easily fluctuating indicators” (e.g., purity of chemical raw materials, concentration of liquid raw materials);

• Dual testing: IQC specialists conduct on-site testing for routine indicators (e.g., dimensions, appearance). For key indicators (e.g., component content, microbial levels), send samples to laboratories for testing with precision instruments (e.g., high-performance liquid chromatographs, atomic absorption spectrophotometers). Archive test reports for future reference;

• Abnormality handling: If sampling fails, immediately initiate “secondary sampling” (double the sampling ratio). If the second sampling also fails, classify the entire batch as unqualified, prohibit warehousing, require suppliers to return or replace the goods, and record the incident in the supplier quality ledger.

• Divide storage areas by raw material characteristics and define environmental requirements:

• • Temperature- and humidity-sensitive materials (e.g., electronic components, pharmaceutical raw materials): Store in constant-temperature, constant-humidity warehouses. Control temperature at 20±5℃ and humidity at 40%–60%. Equip warehouses with temperature and humidity recorders for real-time monitoring and automatic alarms;

• • Corrosion- or oxidation-prone materials (e.g., metal plates, chemical reagents): Store in sealed warehouses. Coat metal raw materials with anti-rust oil or wrap them in anti-rust paper. Store chemical reagents separately and away from fire sources;

• • Food-grade raw materials: Store in clean warehouses, isolated from non-food raw materials. Install UV disinfection equipment in warehouses and conduct regular cleaning (once a week).

• Clear labeling: Attach labels to each storage area and shelf, indicating “raw material name, specification, warehousing date, shelf life, and storage requirements”. This avoids misplacement or confusion (e.g., mixing ordinary plastics with food-grade plastics).

• During warehousing, sort raw materials by “production date/warehousing date”. Place earlier incoming raw materials near the warehouse exit;

• During outbound processing, prioritize the use of the earliest incoming raw materials. This prevents raw materials from exceeding their shelf life or deteriorating due to prolonged storage (e.g., rubber raw materials tend to harden after 6 months of storage, which affects subsequent processing);

• Regular inventory checks: Conduct monthly inventory checks of stored raw materials. Inspect for expired, deteriorated, or abnormally stored materials (e.g., damaged packaging). Isolate and handle problems immediately upon discovery.

• Identify “stages with the greatest impact on raw material quality” in the production process and set up monitoring points:

• • Example 1 (Plastic injection molding): During the raw material melting stage, monitor “melting temperature (e.g., 180–220℃ for PP materials) and screw speed (50–80 rpm)”. Excessive temperature causes raw material degradation, while insufficient temperature leads to incomplete melting;

• • Example 2 (Metal stamping): During the stamping stage, monitor “stamping pressure (e.g., 100–120 MPa) and mold temperature (25±5℃)”. Excessive pressure causes metal deformation, while insufficient pressure prevents proper forming.

• Use automated equipment to collect data in real time (e.g., temperature sensors, pressure sensors). Trigger alarms immediately when data exceeds the qualified range and stop production to investigate the cause (e.g., changes in melting temperature adaptability due to different raw material batches).

• Small differences may exist between different batches of raw materials (e.g., particle size, density), so process parameters need to be adjusted based on actual conditions:

• • Example: A textile factory uses two batches of cotton yarn. Batch A has a moisture content of 12%, while Batch B has a moisture content of 8%. If the same drying temperature (80℃) is used for both, Batch A remains damp after drying, and Batch B becomes brittle due to over-drying. To solve this, adjust the drying temperature to 85℃ for Batch A and keep it at 80℃ for Batch B. This ensures the moisture content of both batches is controlled at 6%–8% after drying.

• Establish a “raw material batch-process parameter” correspondence table. Record the optimal process parameters for each batch of raw materials. Reuse these parameters for subsequent batches of the same raw material to reduce debugging time and quality fluctuations.

• Assign a unique “raw material batch code” (e.g., “MAT-20240528-001”, including the date and batch number) to each batch of raw materials during warehousing;

• During production, correlate the “raw material batch code” with the “finished product traceability code” (e.g., “PROD-20240528-001”). Record this correlation in the Manufacturing Execution System (MES) to enable reverse traceability from “finished products to the raw material batches used”;

• Coding methods: Use barcodes, QR codes, or RFID tags. Scanning the code allows quick access to information such as raw material batches, incoming inspection reports, and production process parameters.

• If finished products fail inspection (e.g., insufficient strength in a batch of parts), use the finished product traceability code to find the corresponding raw material batch. Check the incoming inspection report for that batch (e.g., whether there were component non-conformities) and the production process parameters (e.g., whether there was insufficient stamping pressure);

• If the issue is confirmed to be caused by raw materials (e.g., the tensile strength of the metal raw material batch is below the standard), immediately stop using the remaining raw materials of that batch, recall finished products that have entered the market, and require the supplier to rectify the problem. If the issue is caused by processing (e.g., low stamping temperature), optimize the process parameters and provide training for operators;

• Regular reviews: Monthly statistics on “finished product non-conformity rates related to raw materials”. Analyze high-frequency issues (e.g., persistently high non-conformity rates for a specific type of raw material) and optimize suppliers or inspection standards accordingly (e.g., add component testing items for that type of raw material).

• Regularly collect and analyze key indicators:

• • Raw material side: Supply pass rate of each supplier, incoming non-conformity rate of different raw materials, and deterioration rate of stored raw materials;

• • Production side: Finished product pass rate for different raw material batches, number of process parameter adjustments, and number of raw material quality abnormalities during production;

• Visualize data with charts (e.g., bar charts to compare the pass rates of different suppliers, line charts to track changes in the non-conformity rate of a specific raw material). Identify weaknesses (e.g., a supplier with a persistently low pass rate, a type of raw material with a high storage deterioration rate).

• Address supplier issues: Require suppliers with low pass rates to submit rectification plans. Eliminate suppliers that fail to rectify the problem and introduce new suppliers to fill gaps;

• Address inspection issues: If a type of raw material passes incoming inspection but causes quality fluctuations during production, optimize the inspection standards (e.g., add “processing adaptability testing” for the raw material to simulate production conditions and test its performance);

• Address storage issues: If a type of raw material has a high deterioration rate in storage, improve storage conditions (e.g., add dehumidification equipment, replace packaging with more sealed options);

• Regular audits: Conduct quarterly audits of the Supplier Access Standard, Incoming Inspection Specification, and Storage Management Specification. Revise these documents based on updates to industry standards (e.g., new national raw material safety standards) and changes in enterprise production needs (e.g., special raw materials for new products).

DreamWe inverter performance? Measured performance and user evaluation analysis
In the industrial equipment and pump control system, the performance of the inverter directly affects the operating efficiency and stability of the equipment.DreamWe as a brand focusing on frequency conversion technology, its inverter performance in the market has attracted much attention. In this paper, we will analyze the actual performance of DreamWe inverter through actual measurement data and user feedback, and provide reference for users who have the need to choose and buy.
First, a wide range of adaptability: covering multiple types of pumps and voltage scenarios
One of the core advantages of DreamWe inverters lies in its strong adaptability. Tests show that whether it is a family or small industrial scenes commonly used single-phase 220V water pump (such as water pumps, small submersible pumps), or large industrial equipment equipped with three-phase 380V water pumps (such as centrifugal pumps, deep-well pumps), it can be stable and compatible.
In the test of different power pumps, single-phase water pumps below 1.5kW connected to DreamWe inverters, the peak starting current was reduced by about 30% compared with direct starting, effectively reducing the impact on the power grid; while 380V centrifugal pumps above 5.5kW were adapted and the voltage fluctuation during operation was controlled to within ±2%, with no shutdowns caused by unstable voltage. This means that DreamWe inverters can provide reliable support for both low-power civil and high-power industrial scenarios.
Test Performance: Efficiency, Stability and Energy Saving
1. Operation Efficiency: Enhancing the Working Efficiency of Water Pumps
In a continuous 8-hour running test for a 1.1kW single-phase submersible pump, the conversion efficiency of DreamWe frequency converter is stable at more than 95%, which is 3%-5% higher than that of ordinary frequency converters. Its vector control technology can adjust the motor speed in real time, so that the pump automatically reduces its speed when the flow demand is low, avoiding the waste of energy caused by the “big horse and small car”. Data show that under the same working conditions, the average daily power consumption of water pumps using DreamWe frequency converter is about 12% less than that of traditional control methods.
2. Stability: Ability to cope with complex working conditions
In the test of simulated voltage fluctuation (voltage fluctuates between 180V-240V in 220V scenario, and between 340V-410V in 380V scenario), the over-voltage/under-voltage protection of DreamWe frequency converter responds quickly, and the protection mechanism can be triggered within 0.3 seconds to prevent the pump motor from burning due to the abnormal voltage. Meanwhile, in the humid environment (85% humidity) and dusty environment, its sealing design effectively prevents the components from moisture or dust accumulation, and it runs continuously for 30 days without failures.
3. Intelligent Functions: Simplify Operation and Monitoring
DreamWe inverters are equipped with LED displays that can show parameters such as speed, current and temperature in real time, so that users can keep track of the operating status without additional equipment. Some models support remote control function, and through the cell phone APP, users can adjust the speed of the pump or check the fault code. This design is especially well received in industrial scenarios, which reduces the cost of manual inspection.
User Evaluation: Feedback from Real Scenarios
1. Feedback from Industrial Users
The person in charge of a chemical factory, which purchased three DreamWe 380V inverters for controlling 6kW centrifugal pumps, said, “In the past half year of operation, the equipment has never been shut down due to inverter failure, and the monthly electricity cost has saved nearly 2,000 yuan compared with the previous brand, so the stability and energy saving have exceeded expectations. Stability and energy saving are beyond expectation.”
2. Feedback from Civil Scene
A farmer who installed a 220V water pump mentioned: “The voltage at home is not too stable, and the water pump often tripped in the past, but after replacing the DreamWe frequency converter, even if the voltage fluctuates, the water pump works normally, and the pumping speed is more uniform than before.” 3.
3. Maintenance master evaluation
engaged in water pump maintenance for many years, Mr. Wang said: “DreamWe inverter failure rate is very low, and occasional problems, the fault code is clear, troubleshooting is very convenient, and it is very friendly to our maintenance staff.”
Fourth, summarize: DreamWe inverter is worth choosing?
From the measured data and user feedback, DreamWe inverter is outstanding in terms of adaptability, efficiency and stability, especially in the scenario of large voltage fluctuations, the advantages are obvious, and the energy-saving effect has been verified in multiple scenarios. Whether it is a small power pump for civil use or a high-power device for industrial use, DreamWe can provide reliable control support. If you are looking for an inverter that combines performance and cost-effectiveness, DreamWe is undoubtedly worth considering!

We can introduce the inverter from the aspects of speed regulation performance, energy saving effect, protection function, compatibility, etc. The following are the details:
Excellent speed regulation performance: Our inverter adopts advanced control technology, which can adjust the proportional relationship between output voltage and frequency in real time according to load requirements. It has a wide speed regulation range, high precision, fast response speed, and can accurately meet the control requirements of motor speed under different working conditions.
Significant energy saving effect: It can automatically adjust the power supply voltage and frequency according to the actual load of the motor, so that the motor can run efficiently even at low load and reduce energy loss. For equipment such as pumps and fans, the power consumption of the motor is proportional to the cube of the speed. The frequency conversion speed regulation can greatly save electricity.
Perfect protection function: It has multiple protection functions such as overcurrent, overvoltage, overload, overheating, undervoltage, short circuit, etc. When the motor or inverter is abnormal, it can quickly detect and cut off the power supply or reduce the motor speed, effectively preventing equipment damage and ensuring safe and stable operation of the system.
Excellent soft start function: It can realize the soft start of the motor, so that the voltage is slowly increased from zero to the rated voltage, avoiding the impact torque during the startup process, reducing the impact on the power grid and equipment, and extending the service life of the motor and related equipment.
Strong compatibility: It can be compatible with various types of motors, such as asynchronous motors, synchronous motors, etc. Whether it is a common standard motor or some special specifications of motors, it can be well adapted to meet the motor drive needs of different customers.
Intelligent control and communication function: It supports multiple communication protocols and can exchange data with the host computer or other devices to achieve remote monitoring and fault diagnosis. Users can understand the operating status of the inverter in real time through computers, mobile phones and other terminals, which is convenient for parameter adjustment and troubleshooting, and improves the convenience and intelligence level of equipment management.
Adapt to different working conditions: It has good grid adaptability and can operate stably under various complex grid environments such as voltage fluctuations and frequency changes. At the same time, corresponding protection measures are adopted for different application environments, such as high-efficiency protection circuit boards, which can provide better anti-interference ability and durability.