Photovoltaic Inverter

In the application of photovoltaic inverter (PV inverter), current sensor are used in following two places;
1. DC Current Detecting and
2. AC Current Detecting.

In this page, we would like to propose you our recommendation of AKM products in each place with its superiority.

1. DC Current Detecting

On the DC side of PV inverter, current detection is required for 1.MPPT control to maximize power generation efficiency and 2. overcurrent detection caused by short circuit.

For improvement of system efficiency and realization of minituarization, it has been a challenge to achieve both high accuracy(low sensitivity drift) that correspond to MPPT control in current detection circuit and fast response required for over current detection at the same time.

If you use AKM's current sensor (coreless current sensor IC) ,  it is able to improve system efficiency and make it small size without compromising its safety function, because it realize high accuracy of 1.6% F.S. or less and fast response time of 1μsec or less (*1) in a high-voltage small SMD package.

(*1:For more detail about its data, please click here for Application Note.)

Besides, on the DC side, current flows in one direction. For the case that direction of the current flow is determined, unipolar type product is the most suitable.

By choosing the best unipolar type product, you can use highly sensitive products compared to bipolar type products and achive high resolution.

* Example (in the cace of detecting 10App);  CZ3701 for biploar 200mV/A×10A=2000mV, CZ3720 for unipolar 400mV/A×10A=4000mV) 

Advantage of AKM products

  • High accuracy (Low sensitivity drift)
  • Fast response
  • High withstand volgate
  • Small size
  • Low-heat generation

Our recommendation

Please refer to the "Selection Table".

2. AC Current Detecting

On the AC side of the PV inverter, it is required to generate AC current that eliminates offset current (DC components) as much as possible in order to connect to a commercial power supply and sell electric power.

For AC side, closed-loop current sensors such as fluxgates have been commonly used because of its low offset characteristic, but its size and cost are the problems to be solved.

AKM' s coreless current sensor is the world's first open-loop current sensor in a surface-mounted package with low offset characteristic comparable to closed-loop current sensor.

In addition, because of its structure without a magnetic more, there is no magnetic hysterisis error in principle and you can have stable low offset characteristic.

By using AKM's coreless sensor, high accuracy (low offset drift characteristic) can be achieved while achiving smaller size and lower cost than closed-loop current sensors.

(*2:Please click here about "Types and Characteristics of Current Sensors")

Advantage of AKM products

  • High accuracy (Low offset)
  • Fast response
  • High withstand voltage

Our recommendation

Please refer to the "Selection Table".

Selection Table

Bipolar /
Voltage *
Product Name Product Series
5.0 5.0 60 ± 5.3 to ± 180
Bipolar ≧ 8 800 CZ370x CZ37 Series
0 to 345.2 Unipolar CZ372x 
3.0 50 ± 11.6 to ± 166.6 Bipolar CZ3AGx CZ3A Series
3.3 3.3 ± 12.9 to ± 129.1 CZ3A0x
5.0 5.0 40 ± 33 to ± 60 ≧ 7.2 715 CZ381x CZ38 Series
5.0 5.0 20 ± 4.5 to ± 42 Bipolar
≧ 5 500 CQ330x CQ3 Series
3.3 3.3 ± 8.5 to ± 44 CQ320x
5.0 5.0 ± 10.7 to ± 42 AK310x AK31 Series

* Pollution Degree II with reinforced insulation

'Currentier' series are open-type current sensor ICs which have the world's smallest package, high accuracy, high S/N ratio, and the world's fastest response time.
With these advantages, we will offer the best current sensing solution to wide-ranging applications, such as inverter control, overcurrent detection, and electrical power detection.

* Currentier is a trademark of Asahi Kasei Microdevices Corporation.