How does work ergative structure and how often is it used?
Ergative constructions (作格结构) is one name for a phenomenon where the one subject argument in the intransitive version of the construction is the same as the direct object of the transitive version. These ergative verbs are variously called labile verbs, unaccusative verbs (非宾格动词), anticausative verbs; they have even been posited as reflecting a sort of middle voice (distinct from the more usual active and passive voices for verbs).
For example in Chinese:

TRANSITIVE: 他开了门。
TRANSITIVE-DISPOSAL: 他把门开了。
INTRANSITIVE: 门开了。
Incorrectly inferred: 他开了。

This parallels what happens in ergative-absolutive languages, where the morphosyntactic alignment is like this by default.
This kind of pattern is only defined for those verbs that can both be transitive in some instances and intransitive in others, also known as ambitransitive verbs.
There are some cases where some Chinese verbs can appear ambitransitive where English cannot be. This is often called the &quot;notional passive&quot;:

TRANSITIVE ACTIVE: We defeated them. 我们打败了他们。
TRANSITIVE-DISPOSAL: 我们把他们打败了。
INTRANSITIVE (Chinese only) = NOTIONAL PASSIVE: 他们打败了。
TRANSITIVE PASSIVE: They were/got defeated. 他们被/给打败了。

However, the sentence used in the original question is not even from one of these ambitransitive verbs, as I can't think of a case where 停 alone acts as a transitive verb. Rather the two forms are:

SUBJECT - LOCATION - VERB: 车在院子里停着。
LOCATION - VERB - SUBJECT: [在]院子里停着车。

This is called locative inversion by linguists. In Chinese, it is very often used, although not as frequently as the standard order. Note that it is possible to drop the 在 in the form with location at the front. It can give off an atmospheric, almost poetic vibe, and is a beloved technique of narration and storytelling. This is not too dissimilar to English.