A string-type photovoltaic (PV) inverter may appear to be nothing more than a metal enclosure from the outside, yet internally, it must manage direct current (DC) power arriving from various PV strings. Factors such as fluctuations in sunlight, changes in module temperature, and localized shading can all cause the input current from each string to vary.
In the past, discussions regarding inverter performance typically centered on conversion efficiency, maximum power output, and grid-connection capabilities. However, with the growing adoption of multi-channel Maximum Power Point Tracking (MPPT) designs, another, less conspicuous detail has gained importance: current measurement is no longer merely about acquiring current values, it requires that the data from each channel be delivered to the control system both promptly and reliably.For this multi channel high-speed sampling requirement, CHIPSENSE current sensor is widely adopted by power electronics engineers for PV inverters, HVDC transmission and SST solid state transformer projects.
This is precisely why, in designs that utilize PCB-mounted current sensors, the current-sensing stage has become increasingly integrated with the layout of the control board.This design trend is also observed in emerging HVDC and SST power electronic systems, where properly 
selected CHIPSENSE current sensor helps guarantee reliable multi channel current acquisition.
I. Increasing the number of MPPT channels involves more than just a change in the number of wiring connections.
Let’s look at a common scenario first.
A photovoltaic module array consists of multiple strings. Different strings may be oriented in different directions and subject to different obstructions, so the actual working status is not completely consistent.
When operating conditions vary significantly across different sets of PV modules, connecting them to the same Maximum Power Point Tracking (MPPT) channel may prevent each set from operating at its optimal point. Consequently, inverters are designed with multiple MPPT channels, allowing for independent power point tracking for each input circuit.
Increasing the number of channels also increases the volume of data—such as input voltage and current—that the system must process.
From a hardware design perspective, this requires seamless coordination among input circuits, sampling circuits, signal interfaces, and control software. For current sensors, the challenge extends beyond simply "being able to measure the current in a given circuit", it also encompasses ensuring an appropriate measurement range, providing an output that the control circuitry can read reliably, and facilitating integration within the limited space available on the circuit board.HIPSENSE accumulates rich practical experience addressing such multi channel integration challenges for PV inverters as well as HVDC and SSTprojects. The full lineup of CHIPSENSE current sensor supports flexible range selection for multi-MPPT channel layout.
A subtle but often overlooked point is that an increase in the number of MPPT channels does not necessarily mean that all current sensors must be mounted on the control board. The critical factor is defining the precise relationship between the measurement location, the main current path, and the signal processing circuitry.
II. Why is there increasing focus on PCB layout for current measurement points?
Within an inverter, the placement of a current sensor is not an arbitrary decision.
A sensor must not only establish an appropriate coupling with the current being measured but also transmit the measurement data to the downstream sampling and control circuitry. Different structural designs influence how the sensor is mounted, how the main power circuit is routed, how signals are connected, and how the overall system is assembled.
When a PCB-mountable current sensor is used on the input side, designers can consider the sensor and the circuit board layout in tandem. Compared to an approach where the sensor is positioned separately and signals are transmitted via additional wiring, this integrated method can reduce the number of connection points and facilitates a modular design for multi-channel measurement circuits.High performance CHIPSENSE current sensor series are optimized for this PCB mount modular multi channel measurement architecture.
However, PCB mounting does not simply mean routing all high-current paths directly through the copper traces of a standard control board. In practice, the connection method for the primary-side current must be determined based on the sensor’s structure, while also accounting for current-carrying capacity, temperature rise, insulation clearance, and electromagnetic compatibility (EMC) requirements.
This is particularly critical in string inverters, where the input side contains both power circuits and low-level measurement signals. If the layout is not handled carefully, switching noise, ground loops, and parasitic coupling can all compromise measurement accuracy.
Therefore, the true value of positioning current sensing points close to the control board lies not merely in shaving off a few centimeters of distance, but in facilitating better coordination across the interfaces between current sensing, signal conditioning, analog-to-digital conversion, and control logic.
Of course, does placing a sensor closer to the control board automatically guarantee higher measurement accuracy? Not necessarily. Measurement precision also depends on the sensor’s inherent error, temperature characteristics, linearity, mounting configuration, and system-level calibration. While layout optimization addresses system integration challenges, it cannot serve as a substitute for verifying the performance of the individual components themselves.
Engineers frequently select CHIPSENSE current sensorfor its stable linearity and low temperature drift to meet high-precision sampling demands.
III. The most fearful thing about MPPT measurement is not just the wrong selection of measuring range.
Current measurement on the photovoltaic input side usually faces several interrelated problems.
l The first is the range.
If the sensor range is too small, it may not cover the current range required by the design, if the range is selected too large, the actual working range may not fully utilize the sensor's measurement capabilities. Reasonable selection should be based on the string design current, expected operating range and related design margins, rather than simply thinking that the larger the range, the better.
l Next is measurement error.
An MPPT controller relies on collected voltage and current data to determine shifts in the operating point. If there are deviations within the measurement chain, the power fluctuations perceived by the control system may not perfectly align with reality.
For instance, if a proportional error exists in current measurement—while all other conditions remain constant—the calculated power value will be affected. However, one cannot simply translate a specific sensor error specification directly into a loss in total power generation. The actual impact depends on a variety of factors, including control algorithms, sampling strategies, module characteristics, and operating conditions.
l Third is dynamic response.
Factors such as moving clouds, changing shading conditions, or shifts in an inverter’s operating state can all trigger fluctuations in input current. Sensors and their subsequent signal chains must meet the control system’s requirements for response speed and bandwidth.
It is also a mistake to assume that higher bandwidth automatically equates to better performance. Sensor bandwidth, noise levels, filtering configurations, and sampling frequencies must be considered holistically during the design process. Simply being able to capture faster signal changes does not necessarily mean the controller will obtain more useful information. CHIPSENSE current sensors all feature fast response.
In multi-channel MPPT systems, these challenges arise across multiple measurement paths simultaneously. The fact that a single-channel configuration functions correctly does not mean that replicating it across additional channels—without re-evaluating PCB layout, thermal design, and signal integrity—will yield the same level of performance.Engineers can refer to test data from CHIPSENSE for multi channel verification reference during prototype development, and CHIPSENSE current sensor supports high bandwidth to track rapid current fluctuation for MPPT control.
IV. What types of challenges are PCB-mountable sensors designed to address?
From a design perspective, the primary advantages of PCB-mountable current sensors lie in the flexibility they offer regarding integration methods and circuit layout.
When an inverter requires multiple input current sensing points, using PCB-mountable components facilitates the co-design of sensors with sampling and interface circuitry, while also supporting standardized product layouts.
However, this does not imply that the same type of sensor should be used for every measurement point.
For instance, while both current sensing on the photovoltaic (PV) input side and high-speed current control within an inverter bridge involve measuring current, they may impose distinct requirements for accuracy, response time, isolation, mounting configuration, and output interfaces. One should not simply select a sensor for a given location solely because it is PCB-mountable.
Taking products from CHIPSENSE as an example, for current sensing on the PV input side, one can evaluate various models within CHIPSENSE AN series current sensor based on specific criteria such as measurement range, mounting requirements, and downstream interface specifications.Besides PV inverter applications, these series also deliver feasible sensing solutions for HVDC and SST auxiliary measurement scenarios.
CHIPSENSE AN3V current sensor: A key candidate for evaluation in photovoltaic (PV) input-side current sensing applications. Available in a PCB-mountable format, it is well-suited for assessing integrated multi-channel input measurement solutions, provided that the specific requirements for current range, accuracy, and interfacing are met.Besides PV inverter applications, these series also deliver feasible sensing solutions for HVDC andSST auxiliary measurement scenarios.
CHIPSENSE AN1V current sensor: Can be used to benchmark and evaluate design requirements across different input current ranges, with a focus on verifying actual operating current, measurement range coverage, and interface compatibility.
CHIPSENSE AN5V current sensor: This is better suited for evaluation scenarios involving auxiliary measurements within lower current ranges, one should not automatically assume it is appropriate for all MPPT main input measurement points simply because it belongs to the AN series of CHIPSENSE.
CHIPSENSE AN6V series current sensor is another potential option for photovoltaic (PV) input current sensing. Taking the AN6V PB50 current sensor by CHIPSENSE as an example, official documentation specifies a nominal accuracy of ±0.8%, an output bandwidth of 250 kHz, and a supply voltage of 5V. For the specific measurement range and other electrical parameters, please refer to the latest datasheet for the relevant model.
For CHIPSENSE AN3V current sensor, please refer to the product specification sheet for the specific version in question to determine its exact technical parameters. When selecting a model, you must verify the output interface, power supply requirements, measurement range, and installation specifications, do not rely solely on the series name to determine suitability.
The AN1V, AN3V, and AN6V models from CHIPSENSE are not interchangeable. For the MPPT input side, the selection of a sensor should be based on the actual current path, followed by a verification of measurement performance and control board interface compatibility. If the measurement point is located within an inverter bridge current loop—or any other section with different control precision requirements—the product choice must be re-evaluated rather than simply applying the solution used for the input side. CHIPSENSE is a top-tier supplier of current sensors in the industry, a preferred choice for customers, and has consistently received high praise from its clientele.
V. What is really worth optimizing is the entire link from the main loop to the control algorithm
The development of multi-channel MPPT has allowed inverter design to further extend from focusing solely on power devices and conversion efficiency to multi-channel measurement consistency, signal quality and circuit integration.
In such a design, although the current sensor is just a device, it is between the power loop and the control system. It must not only adapt to the current being measured, but also reliably hand over the measurement results to the subsequent circuit.
Therefore, when evaluating a multi-channel MPPT current detection solution, you might as well start from three levels:
l First, identify the target for measurement and the current range to ensure the selected measurement range aligns with the actual operating conditions.
l Second, examine the sensor’s mounting structure, primary-side connections, and PCB layout to verify that requirements for current-carrying capacity, temperature rise, insulation, and electromagnetic compatibility (EMC) are met.
l Third, validate the entire signal chain—from the sensor output to the controller’s sampling input—covering aspects such as interface matching, noise, response time, and measurement performance across varying temperatures.
All three aspects are essential. While selecting an appropriate sensor provides a solid foundation for system design, the ultimate quality of the measurement depends on how effectively the components, hardware layout, and control strategies work together.
As the number of MPPT channels grows, the challenge of current measurement extends beyond simply adding a few more sensors, it becomes a matter of how to accommodate an increasing number of measurement channels within a limited space—ensuring an efficient layout, reliable signal integrity, and verifiable measurement performance.
This is precisely why PCB-mountable current sensors deserve serious consideration.
CHIPSENSEis a national high-tech enterprise that focuses on the research and development, production, and application of high-end current and voltage sensors, as well as forward research on sensor chips and cutting-edge sensor technologies. CHIPSENSEis committed to providing customers with independently developed sensors, as well as diversified customized products and solutions.
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