US 9,812,988 B2
Method for controlling an inverter, and inverter
Guenter Achleitner, Sattledt (AT); Bernhard Artelsmair, Pettenbach (AT); and Andreas Pamer, Wallern a.d. Trattnach (AT)
Assigned to Fronius International GmbH, Pettenbach (AT)
Appl. No. 14/772,937
Filed by Fronius International GmbH, Pettenbach (AT)
PCT Filed Feb. 28, 2014, PCT No. PCT/AT2014/050046
§ 371(c)(1), (2) Date Sep. 4, 2015,
PCT Pub. No. WO2014/134647, PCT Pub. Date Sep. 12, 2014.
Claims priority of application No. A 50145/2013 (AT), filed on Mar. 5, 2013.
Prior Publication US 2016/0020706 A1, Jan. 21, 2016
Int. Cl. H02M 7/538 (2007.01); H02M 7/537 (2006.01); H02M 3/155 (2006.01); H02M 1/00 (2006.01); H02M 7/48 (2007.01)
CPC H02M 7/537 (2013.01) [H02M 3/155 (2013.01); H02M 2001/0058 (2013.01); H02M 2007/4811 (2013.01); Y02B 70/1491 (2013.01)] 5 Claims
OG exemplary drawing
 
3. An inverter with a DC/DC stage, which comprises at least one main switch (S2), an intermediate circuit, and with a DC/AC stage,
wherein a discharge circuit is provided for discharging the main switch (S2),
wherein the discharge circuit is arranged between the main switch (S2) and the center of two capacitors connected in series in the intermediate circuit, at which capacitors the intermediate circuit voltage (Uz) and at the center of which a partial voltage (Uzt) of the intermediate circuit voltage is applied, and is formed by a bidirectional circuit of first and second switches (SA1, SA2) and an inductivity in series, and
wherein a device is provided for controlling the switches (SA1, SA2) of the discharge circuit and the controlling device is designed such that
the first and second switches (SA1, SA2) are activated in an alternating manner,
the second switch (SA2) is switched on before the main switch (S2) is switched off and a current starts to flow through the inductivity of the discharge circuit until a voltage (US2) reaches the partial voltage (Uzt) and the current reverses and drops to zero,
the voltage (US2) remains at the value of the intermediate circuit voltage (Uz) until the second switch (SA2) is switched off and the first switch (SA1) is switched on, and the inductivity of the discharge circuit starts to charge in an opposite direction,
the main switch (S2) is switched on voltage-free after the voltage (US2) at the main switch (S2) has dropped to zero, and the second switch (SA2) is switched on at a switch-on time of the second switch determined prior to the switching off of the main switch (S2) as a function of a relation of the intermediate circuit voltage (Uz) to the partial voltage (Uzt), and
the switch-on time of the second switch (SA2) is adapted in each cycle until the partial voltage (Uzt) is half of the intermediate circuit voltage (Uz), such that a relation of 2 to 1 is reached.