The Swedish Patent and Registration Office, (Patent- och registreringsverket, PRV), is the government agency in Sweden in charge of patents and other intellectual property rights. In their database, the Swedish Patent Database, you can search for Swedish patents, public patent applications and European patents (EP patents) validated in Sweden.
If you are interested in patents from other countries, the database Espacenet gives you access to more than 130 million documents from all over the world.