[introduction] going up an article is medium, the test instrument that we use R&S is built gave system of a test, use different inductor to measure power transformation implement ripple electric current and switch frequency, pass experimental test and verify the feasibility of all sorts of maths algorithm.

Next, we continue solid operate link, the test device that still uses R&S (oscillograph, power source, probe) build a test system, mix to load respectively the transient state stress of circuit, shed protective stress to have a test too, inductance of saturation of choice of test and verify can let circuit appear any transient state do not stabilize a phenomenon.

Stress checks experimental give typical examples

Stress test test used following plan institute to show PMLK BOOST board. Basically was to use this of circuit board have regulator of step up of pilot of mode of peak value electric current this one part. The major saturated inductor that uses two individual integral to not be 82 cubic millimeter (MSS6122-103) the small saturated inductor with 220 cubic millimeter (MSS7341-712) . This shows, saturated inductor is smaller than be not saturation inductor much.

All character of these two component pass experimental model token, include the effect of temperature. According to working temperature, we got all parameter are worth. Next, used as similar as an experiment experiment device to test this circuit board.

Below this kind of circumstance, we use probe of an electric current to measure inductor electric current only, but the likelihood needs other voltage probe to detect input voltage, output voltage and other signal. Below this kind of circumstance, move to understand adjuster to whether be stabilized, use the FFT function of oscillograph, can detect easily inside frequency domain second harmonic oscillation. We will use these two visible will show this phenomenon.

This stability condition already applied at saturated inductor and blame saturation inductor. In some inductor setting the job is nodded, power of changeover of use saturation inductor may appear to be not stabilized move or periodic move 2 times. Because this sets threshold value, so that see not stable phenomenon.

When 12V of voltage prep above, these two converter that take inductor are periodic stability moves. When stability condition the setting is 12V, saturated inductor and blame saturation inductor are periodic stability moves. And should be its setting under 12V when, saturated inductor expression is aperiodic stability runs the gender, inductor expression is blame saturation periodic stability moves.

Stress checks emulation principle

To prove this from the experiment, undertook the experiment checks emulation mixing. Copy Allah should use following plan institute to show PSIM emulator. Those who use C-block module to pass instruction of a group of C to be able to obtain power inductor any nonlinear equation. Power inductor serves as pressure control current source, get this model block control.

Next graphs emulate a result to make clear, be in when the design below the limit of stable condition when use saturation inductor, can see in time domain, weaveform of inductor electric current is periodic stable. In frequency domain, can see be in only in spectrum about 500kHz office appeared an aiguille or peak value, this is the switch frequency of adjuster.

Drop stable condition limit when voltage besides when, force a system to enter of purpose not steady state, appear next not steady state, but this is not true not steady state. Because be short of those who break output tension to adjust, adjuster continues to will output voltage adjustment to come expectation level. Different is, present inductance electric current is cycle is stabilized no longer, however cycle is stabilized 2 times. This means us to one is occupied the cycle with older sky occupies the cycle with smaller sky with. Final, can see in frequency domain produced second harmonic vibration, this is a problem. Disturb from electromagnetism (EMI) angle looks, it generated more electromagnetism interference.

Stress checks experimental result

Have similar test through the experiment, get the following result. Issueing plan institute to show is periodic the weaveform that stability runs. In spectrum half switch frequency is in, can see have a lesser peak value. This proved adjuster is in the brim that cycle stabilizes.

When reducing voltage to stabilize a condition in order to exceed, get as identical as emulation result time domain weaveform and spectrum, in adjuster place of half switch frequency has greater peak value.

Stress of laden transient state checks

Following plan institute are shown, we undertook stress of laden transient state checks further. The transient state condition below condition of this transient state and worst circumstance is same. From inductor voltaic weaveform can see, when input voltage =12V, inside stability condition limit, did not produce second harmonic vibration. Accordingly, the design considered electric current of the inductance below transient state condition to pass strong case. Good power source design is, the transient state that must consider all possibilities when choosing component and stable state phenomenon and must consider worst case. Accordingly, if what choose saturated inductor to be below worst circumstance (include laden transient state) move correctly, won’t appear so instability, also did not consider the performance that be less than of purpose.

Stress of circuit transient state checks a result

We undertook stress of circuit transient state checks likewise, get as follows pursueing what showing a result. The drop that inductance weaveform red circle shows is the condition of the greatest stress of inductor.

Circuit / stress of laden transient state checks a result

Issueing what chart shows is switch adjuster the condition that runs below online road transient state and condition of laden transient state. Can see not stable phenomenon did not appear in the graph, also did not produce second harmonic vibration.

Shed protective stress test too

When choosing inductor, it must move continuously before shedding protection too. Next graphs are one sheds a test too, load current of green colour specification is reduced or increase. In some dot, cross threshold value, can see in ripple electric current most be in substantially, adjuster is stabilized from cycle any transient state did not appear not to stabilize a phenomenon in moving to stop to run a course.

So far, we finished what inductance saturation commands the influence that move to switch mode power source satisfactorily to explore research. Forecast from mathematical method, to the test and verify below control technology, check a proof through stress finally: With blame (go) saturated inductor is compared, saturated inductor has the narrow measure, good point that drops weight and switch loss. Without doubt, the powerful test platform that R&S builds for all test test, it is the reliable safeguard that finishs these complex jobs.

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