Application and understanding of Rogowski coil sensor

                            Application and understanding of Rogowski coil sensor

Since the Rogowski coil has no ferromagnetic material as the core, there is no problem of magnetic circuit saturation, and there is no problem of signal lag or distortion caused by hysteresis. The entire signal perception and conversion process is instant and linear, so it can be used The Rogowski coil is used to detect arbitrary waveform currents, including DC current. It has a very wide range of applicable frequencies, which is not afraid of overload, and the measurement current range is large. There is no problem of high voltage caused by open coils. It is especially suitable for large current detection occasions. It also has a very big advantage because the Rogowski coil is a toroidal coil with a soft opening, which can be arbitrarily opened and sleeved on the circuit under test without destroying and disassembling the original circuit structure, which is very convenient to use.

The shortcomings of the Rogowski coil and the problems that should be paid attention to when using it.

Rogowski coils have many advantages, but there are also some disadvantages. First, because there is no iron core in the coil, the magnetic field generated in the coil is very weak, and the output signal is also very weak. It is not suitable for detecting small current signals, and the other is due to the coil. The signal magnetic field inside is very weak, easy to be interfered by the environmental magnetic field, which reduces the measurement accuracy. Therefore, it is not suitable for the current sensor to be used in the complicated environmental magnetic field. , Babies who have studied advanced mathematics know that there is a problem with the initial value of the integral in the integral operation. The initial value of the integral must be set. At this point, the teacher must focus on the use of the Rogowski coil and the joint debugging with the integrator. The problem of this is very big. Maybe the result of your measurement is not a shit. We know that the Rogowski coil perceives the differential information of the measured current, that is, it can only sense when the measured current changes. If the measured current does not change (such as a direct current), there is no induced potential in the Rogowski coil, and no matter how you integrate it, it is useless, and the current cannot be measured.

Therefore, we must remember these sequence of operations: one set of loops, two open integrators, three initial values set to 0, four open main circuits, this sequence must not have the slightest error, and special attention is needed once the coil loops are set. , Do not move the position of the ring arbitrarily during the measurement process, because the mutual inductance M between the ring and the main circuit is related to the relative position of the two. Only when the relative positions of the current sensors of the two are determined, the mutual inductance is a constant.

The definition of a sensor under the national standard is: "A device or device that can sense a specified measured part and convert it into a usable signal according to a certain rule (mathematical function law), usually composed of sensitive components and conversion components", China Internet of Things School Enterprise Alliance believes that the existence and development of sensors give objects the senses of touch, taste and smell, and make objects slowly become alive. "Sensor" is defined in the New Wei-style dictionary as: "From a system Receive power, usually in another form to send power to the devices in the second system".

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