Edwards, 23, has scored three goals in 127 games for the Shrimps since joining from Blackburn Rovers in May 2014, with two in 50 appearances last season.
The centre-half was named player of the year at Morecambe's awards night.
He is the third signing for the League One newcomers after the arrivals of Ruben Lameiras and Lionel Ainsworth.
Find all the latest football transfers on our dedicated page.

11 May 2016 Last updated at 08:17 BST
Matthew Oliver paid more than one thousand pounds for the seed which came from the current world record holder grown in Switzerland.
The winning pumpkin weighs 165 stone, so Matthew's would need to weigh-in at more than a tonne to beat that.

The Gills are in the relegation zone following a run of one win in 12 games.
Taylor told BBC Radio Kent: "If the chairman picked up the phone and said 'Peter, that's it, you're not having any longer' I would totally understand.
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"The majority of the fans probably want me out. What I would like to have here is a lot more time."
Gillingham have only won three of their 16 league games this season and are currently two points from safety.
Taylor led the club to 17th place in League One last season after taking charge in October, initially as interim manager, and subsequently targeted a mid-table finish this season.
The 61-year-old received the backing of Scally last month but accepts that it is hard for supporters to show patience while they are struggling.
"I understand the fans' frustrations. We were all expecting a better season than we are having," he said. "We are in a bit of a hole and need to dig ourselves out of it.
"I really do feel that there is a good squad here but we are not showing it at the moment. I would love longer.
"One win in 12 league matches is not good enough. I lost my job at Palace when we had one defeat in five.
"If the chairman sacked me I couldn't complain and I wouldn't complain. Me and the chairman wouldn't fall out either. I am not going to walk away. I am desperate to turn it around and I do honestly feel I will do. I am very determined to."
Taylor overhauled Gillingham's squad during the summer, making eight permanent signings.
He says injuries have played a part in their struggles so far this season, with goalkeeper Stuart Nelson (thumb), utility man Aaron Morris (hamstring), midfielder Doug Loft (Achilles) and striker Danny Kedwell (knee) all missing chunks of the campaign.
"If we'd have had no injures whatsoever then I would expect to be gone by now," Taylor, who had a spell as England's caretaker manager in 2000, said. "There are reasons why we have got a lack of form and confidence.
"I don't think I've ever been able to put a consistent team out. It doesn't half mess you about when you are a squad of our size in League One.
"You need your best players available all the time. Too many times, we have had some important players unavailable and that would affect any team.
"I don't want to make excuses but I just want to clear it up with people out there that are unhappy. I am enjoying every second of the job apart from the results. I am determined to improve them."

Whilst on patrol over Winnipeg, the chopper's crew accidentally turned on its loudspeaker allowing members of the public below to hear them.
Those listening say they heard pilots swearing and discussing oral sex.
Winnipeg Police Service say some of the "conversation was inappropriate" and have promised an internal review.
Brandi Armstrong told CBC news that she had been sitting in her garden on Monday evening as the helicopter flew over and was shocked by the exchange.
"My jaw hit the ground; eyes bulged out," she said.
She added that she would like to see the pilots punished. The police say that they are considering disciplinary measures.
Another resident walking near the city's legislature building overhead a different, expletive-laden discussion about money.
The officers were unaware that the loudspeaker was on due to the noise from the helicopter's engine.
Residents listening below began to tweet to the city's police department as the pilots continued talking.
Plymouth Argyle have signed defender Ryan Edwards from Morecambe on undisclosed terms after agreeing a compensation package.
[NEXT_CONCEPT]
It may be five months until Halloween, but for one gardener it'll be a nail biting wait to see if his seed grows into the biggest pumpkin in the world.
[NEXT_CONCEPT]
Gillingham manager Peter Taylor says he would understand if he was sacked by chairman Paul Scally, but has pleaded for more time at the League One club.
[NEXT_CONCEPT]
Canadian police have apologised after an explicit conversation was inadvertently broadcast from one of its helicopters.