STEVAL-IHM006V1 Circuit Description

AN2316 - Application Note

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STEVAL-IHM006V1 Circuit Description

This ST-patented solution uses a working switch mode to solve third harmonic problems.

The base circuit can be viewed as a mains voltage double-chopper without any preliminary

AC/DC conversion type (see

Figure 1 on page 6).

Note:

The AC chopper STEVAL-IHM006V1 provides customers with a demo that regulates the

voltage in AC motors or loads of up to 300W. This allows the user to demonstrate smooth,

silent, and efficient regulation with respect to TRIAC solutions.

The double-chopper is a device which energizes the load beginning from any level of the

sinusoidal voltage wave and demagnetizes the load with a freewheeling current system,

thereby obtaining voltage and current regulation of the load.

Starting from a perfect sinusoidal-shaped mains curve, the regulated current is also

sinusoidal for all the power levels that the user desires to transfer to the load. By neglecting

the electronic device losses, the circuit incoming power S is equal to the outgoing power:

Equation 1

where,

Equation 2

The circuit operates as a converter, particularly as an AC/AC converter or transformer. It has

no limitation in terms of load impedance since it works with both, inductive and ohmic loads,

with notable angles between the current and the voltage.

SV

AC R MS

()

⋅

V

LOAD R MS

()

=

I

LOAD R MS

()

⋅

=

I

LOAD R MS

()

I

AC R MS

()

---------------------------------------

V

AC R MS

()

V

LO AD RM S

()

------------------------------------------

=