Passive Voice in Academic Writing
In Slovak and Czech we are taught to avoid using passive voice, as it is considered “nonSlavonic”. On the other hand, passive voice is typical for languages of Germanic origin. And that is why writing academic texts in English is so easy — you are advised to avoid the first person (either singular, or plural — the so called “authorial plural”), so you can use passive. And what will you do in Czech or Slovak when you want to avoid the first person? English is definitely a perfect language to write in. 
Passive voice is sometimes used to avoid mentioning the agent (because of “the author’s modesty” or when it is not important). Most often it is used because the object is the more important focus of the information. When we want to emphasize some fact, we put it at the beginning of a sentence. Since English has a very strict word order (the subject is always at the beginning of a sentence, not an object), there is no choice: you must use the passive voice.
However, don’t use passive voice when it can cause confusion about the author (agent): The research will be continued during next three years. (Who will continue – you or somebody else?) During the last four years actions were carried out to correct the problems caused by this project. (Who carriedout the actions? Is or isn’t it important?)