Active clamp flyback power converter. At least some of the example embodiments are methods including: activating a main FET and thereby inducing positive current flow in a primary winding, the positive current flow resulting in reverse biasing of a rectifier of a secondary circuit; deactivating the main FET and thereby forward biasing the rectifier in the secondary circuit and causing current flow in the secondary winding; activating a clamp FET and thereby coupling a clamp capacitor to a leakage inductance of a transformer, the primary circuit having initially a positive current flow through the primary winding and then a negative current flow through the primary winding; and regulating the negative current flow through the primary winding.