Philadelphia came into the game with two power-play goals on their previous 19 chances over six games, but scored on their second and third opportunities against the Canucks.
Simmonds gave the Flyers a 1-0 lead 5:45 into the first period when he sent a rebound through Miller and just over the goal line after a slap shot from Gostisbehere from the top of the left faceoff circle. It was his fourth goal in the past five games.
Voracek scored his first goal in 10 games on a rebound off the rush 1:11 into the second period after a great breakout pass from Gostisbehere and Schenn scored his NHL-leading 14th power-play 1:27 later to make it 3-0.
"The puck was going in," Gostisbehere said. "A different look on the [power play] helps a little bit."
Markus Granlund and Jannik Hansen scored for the Canucks (26-28-6), who have three wins in the past 11 games. They start their five-day break on Monday.
Vancouver is four points behind the Calgary Flames for the second wild card into the playoffs from the Western Conference.
The Canucks were 0-for-4 on the power play and only generated two shots.
"Our specialty teams let us down," coach Willie Desjardins said.
Ryan Miller, starting back-to-back games for the first time this season, made 25 saves.
"Stamina was there, I felt fine," Miller said. "Just not thrilled about the penalty kill situation."