If the TV show you are thinking of was from the 90s and had a similar look and feel to Power Rangers, then you might be thinking of VR Troopers.
The show focused on three teenagers in their late teens, Ryan Steele, Kaitlin Star, and J.B. Reese, living in the fictional West Coast town of Cross World City, California. They regularly attended and were teachers at "Tao's Dojo," a karate studio. Ryan was the most focused martial artist; J.B. was the computer wizard; while Kaitlin was a photographer & budding reporter for the local newspaper, the Underground Voice Daily. One day, Ryan's search for his long-missing father led him and his two friends to a strange laboratory. Inside, a digitized head of Professor Horatio Hart (who is a friend of Ryan's father Tyler) explained the truth about his life's work of having developed extremely advanced virtual reality technology in secret. "VR" is a dimension existing alongside our own; within it lie mutants bent on conquering both worlds. The main ruler of these is a creature known as Grimlord, who, unbeknownst to anyone on Earth, has a human identity as billionaire industrialist Karl Ziktor. As Karl Ziktor tries to overcome the barriers of the true reality to allow his armies easy passage from virtual world, the responsibility falls to Ryan, Kaitlin, and J.B. of defending the planet on both sides of the dimensional barrier. They have assistance in the form of armored bodies having incredible firepower. This included eventual additions to their arsenal, such as a Turbo Cycle, Techno Bazooka, VR Troopertron, VR Shoulder Cannon, VR Battlecruiser/Interceptop and a flying, laser-blasting Skybase.
