Here is a quick SQL script that will get back information on SQL availability groups, including the role of each server. This can help you find the primary server in an availability group.

IF SERVERPROPERTY ('IsHadrEnabled') = 1
BEGIN
    SELECT
        AvailabilityGroup.name AS AvailabilityGroupName,
        ReplicaClusterStates.replica_server_name as ServerName,
        ReplicaStates.role_desc as ReplicaRole,
        Listeners.dns_name as DnsName
    FROM
        sys.availability_groups_cluster AS AvailabilityGroup
    INNER JOIN
        sys.dm_hadr_availability_replica_cluster_states AS ReplicaClusterStates ON ReplicaClusterStates.group_id = AvailabilityGroup.group_id
    INNER JOIN
        sys.dm_hadr_availability_replica_states AS ReplicaStates ON ReplicaStates.replica_id = ReplicaClusterStates.replica_id
    INNER JOIN
        sys.availability_group_listeners AS Listeners ON Listeners.group_id = ReplicaStates.group_id
    ORDER BY
        ReplicaStates.role_desc
END

The primary server for each availability group will be listed with a replica role of PRIMARY.